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Test Code : VCS-256
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: 84 true Questions
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Sep 18, 2018Stephanie Simone
Veritas applied sciences, company of commercial enterprise statistics coverage and application-defined storage options, is entering into a government-wide constrict for the U.S. generic services Administration (GSA), proposing federal corporations with data governance and cloud statistics management application.
below the settlement, govt corporations could occupy access to Veritas data coverage and cloud solutions at negotiated costs to allow for stronger information management.
The settlement is derived from the GSA IT schedule 70 and totally helps the Federal advice know-how Acquisition Reform Act (FITARA) Enhancement application.
The constrict brings Veritas’ enterprise information management portfolio to All eligible federal, state, native, and tribal government groups.
These agencies can build upon the statistics coverage groundwork of Veritas NetBackup and add further facts management capabilities to accelerate their cloud initiatives.
some of the initial offerings encompass:
For extra guidance about this information, consult with www.veritas.com.
LAS VEGAS--(business WIRE)--Veritas applied sciences, the leader in tips management, nowadays introduced at AWS re:Invent current capabilities for InfoScale and NetBackup designed to optimize industry application migration and simplify facts insurance policy deployment inside Amazon web functions (AWS) environments. Veritas InfoScale offers application-defined storage for the cloud and helps exist sure application performance, scale and resiliency requirements are met. additionally, retaining these purposes and other cloud-primarily based workloads has now been made even less demanding with the current Amazon computing device realistic (AMI) for NetBackup. These latest capabilities exist a Part of a bunch of present Veritas cloud statistics administration options that aid a variety of AWS exercise instances, from facts governance and protection to migration and cataclysm restoration.
As organizations seem to shift from upfront capex investments to pay-as-you-go opex models, many are prioritizing AWS materials to replace expensive on-premises infrastructure. in fact, in keeping with Veritas research, 53 percent of mission-vital applications could exist within the public cloud this yr. This accelerating shift shows that before refreshing on-premises hardware, groups are looking first to the cloud. besides the fact that children, one most considerable roadblock to without problems “lifting and shifting” functions enjoy Oracle, SAP, and other aid intensive workloads is the efficiency and resiliency tradeoffs. while IT has the option of refactoring these functions to labor natively within the cloud, doing so can furthermore exist both a big time dedication and an expensive undertaking.
Veritas InfoScale permits the precipitate and cost-effectiveness of lifting and shifting to AWS whereas assisting ensure the performance, scalability and resiliency of these industry functions. the current NetBackup AMI simplifies information protection deployment—both out and in of the cloud—as a Part of the NetBackup platform’s lone pane of glass sustain and finished retort to give protection to All actual, digital and cloud-based mostly workloads.
today’s announcement serves as a vital proof point of Veritas’ system to deliver cloud facts management options that address All principal areas of cloud transformation:
“Our purchasers are leveraging Veritas options to combine Amazon S3 into their records lifecycle management strategy,” pointed out Mike Palmer, government vice president, chief product officer at Veritas. “hobby in stirring tier-one commercial enterprise applications comparable to Oracle and SAP to the cloud is becoming. Veritas is main the efforts to enable these organizations occupy a seamless, scalable and within your means retort to entry, share and leverage cloud storage without having to sacrifice performance or resiliency.”
“As more organizations increasingly flip to a number of styles of clouds to dash some or All of their mission-important purposes, the means to migrate and maneuver facts between and throughout platforms—no longer simply in any respect, however quite simply—turns into vital,” referred to label Peters, commemorate Director & Senior Analyst, industry strategy community. “by means of creating solutions for these hybrid cloud environments, and notably building-in assist for AWS, Veritas is providing valued clientele with a wonderful strategy to both maneuver their facts and furthermore to benefit seamless access to the realm’s greatest public cloud provider.”
Veritas is a gold sponsor of AWS re:Invent 2016. For conference attendees drawn to discovering extra about Veritas cloud data administration offerings for AWS, gladden seek advice from us at sales space #632. additionally, comply with us on twitter @Veritasllc and occupy interaction with us the usage of #reInvent or #ReInvent2016.
About Veritas applied sciences
Veritas technologies permits businesses to harness the vigor of their information, with advice administration options serving the area’s biggest and most knotty environments. Veritas works with corporations of All sizes, including 86 percent of world Fortune 500 companies, improving information availability and revealing insights to pressure competitive knowledge. www.veritas.com
So when the court docket ruled that the web shutdown was illegal and connectivity may silent exist restored, they wrote that the grounds for the decision had been now not enough to avoid the govt from shutting down the web again.
To exist sincere, the govt in Zimbabwe has long gone towards courtroom rulings before although, it's prudent to leave defiance of the courts because the most effectual means out for the executive than to depart the challenge of legality placing.
Already some senior executive officials are promising that the cyber web can exist shut down once again and are making precipitate statements like, “traders don’t need the information superhighway.” Even the president has justified the shutting down of the cyber web.
Veritas has sent out a bulletin which fairly much consents with their assertion that the problem of the legality and constitutionality of the Interception of Communications Act is awfully essential. To celebrate a reprieve in accordance with a technicality will nonetheless leave the govt with an excuse to shut down the cyber web. subsequent time they're going to simply originate the president signal the warrant.
here is the complete Veritas bulletin:
On Tuesday fifteenth January, the 2d day of a stay-away called by course of the Zimbabwe Congress of alternate Unions, All internet functions across the nation had been terminated below govt directives. Econet, the country’s greatest cellular telecommunications operator and cyber web service company [ISP], issued the following observation to its subscribers:
“additional to a warrant issued via the Minister of situation within the President’s office for national security throughout the Director-normal of the President’s arm acting when it comes to the Interception of Communications Act, internet functions are at present suspended throughout All networks and web carrier providers. they are obliged to behave when directed to carry out so and the recall is past their manage.’’
other ISPs issued identical statements. As All ISPs complied with the Minister of State’s orders, the impact turned into to shutdown cyber web functions, e-mail features and sociable media structures such as WhatsApp, fb and Twitter.
On Wednesday sixteenth January, in a missive to the Minister of State, attorneys appearing for 3 particular person journalists and the Zimbabwe Chapter of the Media Institute of Southern Africa [MISA Zimbabwe], demanded instant revocation of his warrant, failing which criminal lawsuits would exist instituted. There become no response and no revocation of the warrant.
courtroom software and the government’s Response
ZLHR and MISA Zimbabwe v Minister of situation for national safety and Others – the cyber web Shutdown Case [link] – gladden commemorate this hyperlink to examine the finished utility, the Opposition papers filed via the Director-commonplace of CIO and the high court docket order.
Later the very day, hence, an imperative chamber utility turned into lodged in the immoderate court docket, Harare, in quest of provisional suspension of the warrant and orders to ISPs to renew functions, pending the supply of a remaining order atmosphere apart the warrant. The candidates occupy been Zimbabwe attorneys for Human Rights and MISA Zimbabwe; the respondents were the Minister of State, the Director-time-honored of Intelligence, the President and the ISPs Econet, NetOne and Telecel Zimbabwe.
This admirably finished application raised numerous grounds justifying the atmosphere apart of the warrant, together with: (1) that section 6 of the Interception of Communications Act [“the Act”] did not authorise a blanket ban or suspension, handiest the interception of communications – making a suspension of internet servicesultra vires; (2) that Part 6 of the Act is incompatible with the constitution, principally section 61 – freedom of expression, and Part fifty six – equality of All under the legislations. keeping changed into furthermore taken to reveal that the warrant had been issued by the Minister whereas the President had reserved administration of the Act to himself via SI 212/2018.
The Director-universal filed a exist alert of opposition on Friday 18th January, supported by an affidavit from the Deputy Director, Administration. The affidavit admitted that the Minister of situation turned into the adult who had issued a “directive” ordering the blanket ban below locality 6 of the Act, and that the President had reserved the administration of the Act to himself. however the Deputy Director firmly defended the Minister’s action as permitted by means of the Act and justified by course of the circumstances rife within the country [for instance, the exercise of the Internet and sociable media to foment the violence and other unlawful conduct that accompanied ZCTU stay-away]. She furthermore emphatically disputed the other prison and constitutional grounds superior within the utility.
The listening to before Mr Justice Tagu
The hearing of the application took vicinity earlier than Mr Justice Tagu on Monday twenty first January, as befitted its urgency. It become to had been held in the decide’s chambers however was moved to a courtroom as a course to accommodate these members of the press and public wishing to attend.
tips for the applicants commenced by means of soliciting for the referee to resolve the case on the primary preparatory aspect that the Minister of State, now not being the adult legally accountable for the administration of the Act and therefore now not being “the Minister” for the goal of the Act, changed into no longer the proper functionary to activity the powers conferred on “the Minister” with the aid of locality 6 of the Act, whether with the aid of issuing a “warrant” or a “directive”.
This preparatory aspect become straightforward. locality 6 of the Act – the Part beneath which the Minister became said to occupy acted – confers vigor to situation directives and warrants on the “Minister”. Part 2 of the Act defines “Minister” as which means “the Minister of Transport and Communications or another Minister to whom the President may additionally every now and then apportion the administration of this Act”. The President has not assigned the administration of the Act to the Minister of State; on the opposite, based on SI 212/2018 of nineteenth October 2018, he has reserved to himself the administration of the Act, as he's entitled to carry out in terms of locality 104(1) of the charter. Ergo, the Minister of situation has no powers below Part 6 of the Act.
Veritas in its constitution Watch 2/2019 of 19th January [link] made this factor, and furthermore cited that the internet shut down become unconstitutional.
As information for the Minister and the Director-frequent had [and could have] no reply the preparatory factor, the referee then proceeded to resolve the case in favour of the applicants – without listening to oral controversy on the larger criminal concerns raised with the aid of the application.
This preparatory factor became easy. section 6 of the Act – the locality below which the Minister became referred to to occupy acted – confers vigour to concern directives and warrants on the “Minister”. locality 2 of the Act defines “Minister” as import “the Minister of Transport and Communications or every other Minister to whom the President can furthermore now and again apportion the administration of this Act”. The President has no longer assigned the administration of the Act to the Minister of situation or some other Minister; on the contrary, in accordance with Statutory Instrument 212/2018 of nineteenth October 2018, he has reserved to himself the administration of the Act, as he is entitled to carry out in terms of section 104(1) of the charter. Ergo, the Minister of situation has no powers beneath section 6 of the Act.
A provisional order become issued giving the respondents ten days to reveal occasions why a closing order may silent no longer exist issued atmosphere aside the Minister’s directives. If the respondents are looking to try this , they need to file the requisite papers with the high court docket within ten days, failing which the case could exist set down for affirmation of the provisional order as an unopposed application.
To regulate the circumstance pending a remaining order, Mr Justice Tagu additionally granted term in-between aid as follows:
suspending forthwith the directives or warrants issued by using the Minister of situation or the Director-everyday shutting down cyber web communications right through the outdated week and any subsequent days of January
ordering ISPs [Econet, NetOne, Telecel and All other holders of telecommunications licences to unconditionally resume plenary and unrestricted cyber web functions to All subscribers
those hoping that the immoderate court would exercise this case to set aside the Minister’s information superhighway shutdown with a ringing condemnation of the Interception of Communications Act as incompatible with the constitutional rights of residents might furthermore occupy been upset by means of a preference on a slender technical point now not involving freedom of expression at all.
There could exist a further war of words in the courts – given press studies on statements this week by executive that the Act as it stands isn't best according to the charter but gives executive the energy, albeit in the course of the redress functionary, to impose a web shutdown and/or to interrupt sociable media purposes every time it believes such action to exist justified.Zimbabwe lawyers for Human RightsZimbabwe Congress of alternate UnionsHigh courtroom
Zimbabwe attorneys for Human Rights (ZLHR) is a no longer for income human rights firm whose core objective is to foster a tradition of human rights in Zimbabwe in addition to cheer the increase and strengthening of human rights in any respect levels of Zimbabwean society via... read extra About Zimbabwe legal professionals for Human Rights
The Zimbabwe Congress of alternate Unions is the country's biggest employee consultant with most of its participants in several sectors of trade in Zimbabwe. It has special pastimes in labour activism and this has resulted in it being linked to opposition political parties principally the... read more About Zimbabwe Congress of exchange Unions
The high court of Zimbabwe is among the advanced Courts of Zimbabwe. The high court offers originally illustration with All high charge and immoderate significance situations. It furthermore has a supervisory jurisdiction over All subordinate courts and tribunals. Appeals from the immoderate courtroom... study greater About high court
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January 24, 2000Web posted at: 12:11 p.m. EST (1711 GMT)
by John Bass and James Robinson, Network World Test Alliance
(IDG) -- It All boils down to what you're looking for in a network operating system (NOS).
Do you want it spare and springy so you can install it any course you please? Perhaps administration bells and management whistles are what you need so you can deploy several hundred servers. Or maybe you want an operating system that's robust enough so that you sleep enjoy a baby at night?
The wonderful tidings is that there is a NOS waiting just for you. After the rash of recent software revisions, they took an in-depth Look at four of the major NOSes on the market: Microsoft's Windows 2000 Advanced Server, Novell's NetWare 5.1, Red Hat Software's Linux 6.1 and The Santa Cruz Operation's (SCO) UnixWare 7.1.1. Sun declined their invitation to submit Solaris because the company says it's working on a current version.
Microsoft's Windows 2000 edges out NetWare for the Network World Blue Ribbon Award. Windows 2000 tops the domain with its management interface, server monitoring tools, storage management facilities and security measures.
However, if it's performance you're after, no product came near to Novell's NetWare 5.1's numbers in their exhaustive file service and network benchmarks. With its lightning-fast engine and Novell's directory-based administration, NetWare offers a much foundation for an enterprise network.
We institute the latest release of Red Hat's commercial Linux bundle led the list for flexibility because its modular design lets you pare down the operating system to suit the chore at hand. Additionally, you can create scripts out of multiple Linux commands to automate tasks across a distributed environment.
While SCO's UnixWare seemed to lag behind the pack in terms of file service performance and NOS-based administration features, its scalability features originate it a stalwart candidate for running enterprise applications.The numbers are in
Regardless of the job you saddle your server with, it has to accomplish well at reading and writing files and sending them across the network. They designed two benchmark suites to measure each NOS in these two categories. To reflect the true world, their benchmark tests consider a wide sweep of server conditions.
NetWare was the hands-down leader in their performance benchmarking, taking first set in two-thirds of the file tests and earning top billing in the network tests.
Red Hat Linux followed NetWare in file performance overall and even outpaced the leader in file tests where the read/write loads were small. However, Linux did not accomplish well handling big loads - those tests in which there were more than 100 users. Under heavier user loads, Linux had a tendency to quit servicing file requests for a short term and then start up again.
Windows 2000 demonstrated needy write performance across All their file tests. In fact, they institute that its write performance was about 10% of its read performance. After consulting with both Microsoft and Client/Server Solutions, the author of the Benchmark Factory testing utensil they used, they determined that the needy write performance could exist due to two factors. One, which they were unable to verify, might exist a workable performance problem with the SCSI driver for the hardware they used.
More significant, though, was an issue with their test software. Benchmark Factory sends a write-through flag in each of its write requests that is hypothetical to occasions the server to update cache, if appropriate, and then force a write to disk. When the write to disk occurs, the write summon is released and the next request can exist sent.
At first glance, it appeared as if Windows 2000 was the only operating system to honor this write-through flag because its write performance was so poor. Therefore, they ran a second round of write tests with the flag turned off.
With the flag turned off, NetWare's write performance increased by 30%. This test proved that Novell does indeed honor the write-through flag and will write to disk for each write request when that flag is set. But when the write-through flag is disabled, NetWare writes to disk in a more efficient manner by batching together contiguous blocks of data on the cache and writing All those blocks to disk at once.
Likewise, Red Hat Linux's performance increased by 10% to 15% when the write-through flag was turned off. When they examined the Samba file system code, they institute that it too honors the write-through flag. The Samba code then finds an optimum time during the read/write sequence to write to disk.
This second round of file testing proves that Windows 2000 is dependent on its file system cache to optimize write performance. The results of the testing with the write-through flag off were much higher - as much as 20 times faster. However, Windows 2000 silent fell behind both NetWare and RedHat Linux in the file write tests when the write-through flag was off.
SCO honors the write-through flag by default, since its journaling file system is constructed to maximize data integrity by writing to disk for All write requests. The results in the write tests with the write-through flag on were very similar to the test results with the write-through flag turned off.
For the network benchmark, they developed two tests. Their long TCP transaction test measured the bandwidth each server can sustain, while their short TCP transaction test measured each server's faculty to wield big numbers of network sessions with minuscule file transactions.
Despite a needy showing in the file benchmark, Windows 2000 came out on top in the long TCP transaction test. Windows 2000 is the only NOS with a multithreaded IP stack, which allows it to wield network requests with multiple processors. Novell and Red Hat verbalize they are working on integrating this capability into their products.
NetWare and Linux furthermore registered stalwart long TCP test results, coming in second and third, respectively.
In the short TCP transaction test, NetWare came out the limpid winner. Linux earned second set in spite of its lack of advocate for abortive TCP closes, a system by which an operating system can quickly tear down TCP connections. Their testing software, Ganymede Software's Chariot, uses abortive closes in its TCP tests.Moving into management
As enterprise networks grow to require more servers and advocate more finish users, NOS management tools become crucial elements in keeping networks under control. They looked at the management interfaces of each product and drilled down into how each handled server monitoring, client administration, file and print management, and storage management.
We institute Windows 2000 and NetWare provide equally useful management interfaces.
Microsoft Management Console (MMC) is the glue that holds most of the Windows 2000 management functionality together. This configurable graphical user interface (GUI) lets you snap in Microsoft and third-party applets that customize its functionality. It's a two-paned interface, much enjoy Windows Explorer, with a nested list on the left and selection details on the right. The console is simple to exercise and lets you configure many local server elements, including users, disks, and system settings such as time and date.
MMC furthermore lets you implement management policies for groups of users and computers using vigorous Directory, Microsoft's current directory service. From the vigorous Directory management utensil inside MMC, you can configure users and change policies.
The network configuration tools are institute in a part application that opens when you click on the Network Places icon on the desktop. Each network interface is listed inside this window. You can add and change protocols and configure, enable and disable interfaces from here without rebooting.
NetWare offers several interfaces for server configuration and management. These tools tender duplicate functionality, but each is useful depending from where you are trying to manage the system. The System Console offers a number of tools for server configuration. One of the most useful is NWConfig, which lets you change start-up files, install system modules and configure the storage subsystem. NWConfig is simple, intuitive and predictable.
ConsoleOne is a Java-based interface with a few graphical tools for managing and configuring NetWare. Third-party administration tools can plug into ConsoleOne and let you manage multiple services. They mediate ConsoleOne's interface is a bit unsophisticated, but it works well enough for those who must occupy a Windows- based manager.
Novell furthermore offers a Web-accessible management application called NetWare Management Portal, which lets you manage NetWare servers remotely from a browser, and NWAdmin32, a relatively simple client-side utensil for administering Novell Directory Services (NDS) from a Windows 95, 98 or NT client.
Red Hat's overall systems management interface is called LinuxConf and can dash as a graphical or text-based application. The graphical interface, which resembles that of MMC, works well but has some layout issues that originate it difficult to exercise at times. For example, when you dash a setup application that takes up a lot of the screen, the system resizes the application larger than the desktop size.
Still, you can manage pretty much anything on the server from LinuxConf, and you can exercise it locally or remotely over the Web or via telnet. You can configure system parameters such as network addresses; file system settings and user accounts; and set up add-on services such as Samba - which is a service that lets Windows clients rep to files residing on a Linux server - and FTP and Web servers. You can apply changes without rebooting the system.
Overall, Red Hat's interface is useful and the underlying tools are powerful and flexible, but LinuxConf lacks the polish of the other vendors' tools.
SCO Admin is a GUI-based front finish for about 50 SCO UnixWare configuration and management tools in one window. When you click on a tool, it brings up the application to manage that item in a part window.
Some of SCO's tools are GUI-based while others are text-based. The server required a reboot to apply many of the changes. On the plus side, you can manage multiple UnixWare servers from SCOAdmin.
SCO furthermore offers a useful Java-based remote administration utensil called WebTop that works from your browser.An eye on the servers and clients
One considerable administration chore is monitoring the server itself. Microsoft leads the pack in how well you can withhold an eye on your server's internals.
The Windows 2000 System Monitor lets you view a real-time, running graph of system operations, such as CPU and network utilization, and remembrance and disk usage. They used these tools extensively to determine the effect of their benchmark tests on the operating system. Another utensil called Network Monitor has a basic network packet analyzer that lets you descry the types of packets coming into the server. Together, these Microsoft utilities can exist used to compare performance and capacity across multiple Windows 2000 servers.
NetWare's Monitor utility displays processor utilization, remembrance usage and buffer utilization on a local server. If you know what to Look for, it can exist a powerful utensil for diagnosing bottlenecks in the system. Learning the import of each of the monitored parameters is a bit of a challenge, though.
If you want to Look at performance statistics across multiple servers, you can tap into Novell's Web Management Portal.
Red Hat offers the gauge Linux command-line tools for monitoring the server, such as iostat and vmstat. It has no graphical monitoring tools.
As with any Unix operating system, you can write scripts to automate these tools across Linux servers. However, these tools are typically cryptic and require a high even of proficiency to exercise effectively. A suite of graphical monitoring tools would exist a much addition to Red Hat's Linux distribution.
UnixWare furthermore offers a number of monitoring tools. System Monitor is UnixWare's simple but limited GUI for monitoring processor and remembrance utilization. The sar and rtpm command-line tools together list real-time system utilization of buffer, CPUs and disks. Together, these tools give you a wonderful overall idea of the load on the server.Client administration
Along with managing the server, you must manage its users. It's no astound that the two NOSes that ship with an integrated directory service topped the domain in client administration tools.
We were able to configure user permissions via Microsoft's vigorous Directory and the directory administration utensil in MMC. You can group users and computers into organizational units and apply policies to them.
You can manage Novell's NDS and NetWare clients with ConsoleOne, NWAdmin or NetWare Management Portal. Each can create users, manage file space, and set permissions and rights. Additionally, NetWare ships with a five-user version of Novell's ZENworks tool, which offers desktop administration services such as hardware and software inventory, software distribution and remote control services.
Red Hat Linux doesn't tender much in the course of client administration features. You must control local users through Unix authorization configuration mechanisms.
UnixWare is similar to Red Hat Linux in terms of client administration, but SCO provides some Windows binaries on the server to remotely set file and directory permissions from a Windows client, as well as create and change users and their settings. SCO and Red Hat tender advocate for the Unix-based Network Information Service (NIS). NIS is a store for network information enjoy logon names, passwords and home directories. This integration helps with client administration.Handling the staples: File and print
A NOS is nothing without the faculty to share file storage and printers. Novell and Microsoft collected top honors in these areas.
You can easily add and maintain printers in Windows 2000 using the print administration wizard, and you can add file shares using vigorous Directory management tools. Windows 2000 furthermore offers Distributed File Services, which let you combine files on more than one server into a lone share.
Novell Distributed Print Services (NDPS) let you quickly incorporate printers into the network. When NDPS senses a current printer on the network, it defines a Printer Agent that runs on the printer and communicates with NDS. You then exercise NDS to define the policies for the current printer.
You define NetWare file services by creating and then mounting a disk volume, which furthermore manages volume policies.
Red Hat includes Linux's printtool utility for setting up server-connected and networks printers. You can furthermore exercise this GUI to create printcap entries to define printer access.
Linux has a set of command-line file system configuration tools for mounting and unmounting partitions. Samba ships with the product and provides some integration for Windows clients. You can configure Samba only through a cryptic configuration ASCII file - a staid drawback.
UnixWare provides a springy GUI-based printer setup utensil called Printer SetUp Manager. For file and volume management, SCO offers a utensil called VisionFS for interoperability with Windows clients. They used VisionFS to allow their NT clients to access the UnixWare server. This service was simple to configure and use.Storage management
Windows 2000 provides the best tools for storage management. Its graphical Manage Disks utensil for local disk configuration includes software RAID management; you can dynamically add disks to a volume set without having to reboot the system. Additionally, a signature is written to each of the disks in an array so that they can exist moved to another 2000 server without having to configure the volume on the current server. The current server recognizes the drives as members of a RAID set and adds the volume to the file system dynamically.
NetWare's volume management tool, NWConfig, is simple to use, but it can exist a miniature confusing to set up a RAID volume. Once they knew what they were doing, they had no problems formatting drives and creating a RAID volume. The utensil looks a miniature primitive, but they give it high marks for functionality and ease of use.
Red Hat Linux offers no graphical RAID configuration tools, but its command line tools made RAID configuration easy.
To configure disks on the UnixWare server, they used the Veritas Volume Manager graphical disk and volume administration utensil that ships with UnixWare. They had some problems initially getting the utensil to recognize the drives so they could exist formatted. They managed to labor around the disk configuration problem using an assortment of command line tools, after which Volume Manager worked well.Security
While they did not probe these NOSes extensively to expose any security weaknesses, they did Look at what they offered in security features.
Microsoft has made significant strides with Windows 2000 security. Windows 2000 supports Kerberos public key certificates as its primary authentication mechanism within a domain, and allows additional authentication with smart cards. Microsoft provides a Security Configuration utensil that integrates with MMC for simple management of security objects in the vigorous Directory Services system, and a current Encrypting File System that lets you designate volumes on which files are automatically stored using encryption.
Novell added advocate for a public-key infrastructure into NetWare 5 using a public certificate schema developed by RSA Security that lets you tap into NDS to generate certificates.
Red Hat offers a basic Kerberos authentication mechanism. With Red Hat Linux, as with most Unix operating systems, the network services can exist individually controlled to increase security. Red Hat offers Pluggable Authentication Modules as a course of allowing you to set authentication policies across programs running on the server. Passwords are protected with a shadow file. Red Hat furthermore bundles firewall and VPN services.
UnixWare has a set of security tools called Security Manager that lets you set up varying degrees of intrusion protection across your network services, from no restriction to turning All network services off. It's a wonderful management time saver, though you could manually modify the services to achieve the very result.Stability and fault tolerance
The most feature-rich NOS is of miniature value if it can't withhold a server up and running. Windows 2000 offers software RAID 0, 1 and 5 configurations to provide fault tolerance for onboard disk drives, and has a built-in network load-balancing feature that allows a group of servers to Look enjoy one server and share the very network designation and IP address. The group decides which server will service each request. This not only distributes the network load across several servers, it furthermore provides fault tolerance in case a server goes down. On a lesser scale, you can exercise Microsoft's Failover Clustering to provide basic failover services between two servers.
As with NT 4.0, Windows 2000 provides remembrance protection, which means that each process runs in its own segment.
There are furthermore backup and restore capabilities bundled with Windows 2000.
Novell has an add-on product for NetWare called Novell Cluster Services that allows you to cluster as many as eight servers, All managed from one location using ConsoleOne, NetWare Management Portal or NWAdmin32. But Novell presently offers no clustering products to provide load balancing for applications or file services. NetWare has an complicated remembrance protection scheme to segregate the remembrance used for the kernel and applications, and a Storage Management Services module to provide a highly springy backup and restore facility. Backups can exist all-inclusive, cover parts of a volume or store a differential snapshot.
Red Hat provides a load-balancing product called piranha with its Linux. This package provides TCP load balancing between servers in a cluster. There is no arduous limit to the number of servers you can configure in a cluster. Red Hat Linux furthermore provides software RAID advocate through command line tools, has remembrance protection capabilities and provides a rudimentary backup facility.
SCO provides an optional feature to cluster several servers in a load-balancing environment with Non-Stop Clustering for a high even of fault-tolerance. Currently, Non-Stop Clustering supports six servers in a cluster. UnixWare provides software RAID advocate that is managed using SCO's On-Line Data Manager feature. All the gauge RAID levels are supported. Computer Associates' bundled ArcServeIT 6.6 provides backup and restore capabilities. UnixWare has remembrance protection capabilities.Documentation
Because their testing was conducted before Windows 2000's generic availability ship date, they were not able to evaluate its hard-copy documentation. The online documentation provided on a CD is extensive, useful and well-organized, although a Web interface would exist much easier to exercise if it gave more than a pair of sentences at a time for a particular attend topic.
NetWare 5 comes with two manuals: a detailed manual for installing and configuring the NOS with wonderful explanations of concepts and features along with an overview of how to configure them, and a minuscule spiral-bound booklet of quick start cards. Novell's online documentation is very helpful.
Red Hat Linux comes with three manuals - an installation guide, a getting started steer and a reference manual - All of which are simple to follow.
Despite being the most difficult product to install, UnixWare offers the best documentation. It comes with two manuals: a system handbook and a getting started guide. The system handbook is a reference for conducting the installation of the operating system. It does a wonderful job of reflecting this painful experience. The getting started steer is well-written and well-organized. It covers many of the tools needed to configure and maintain the operating system. SCO's online documentation looks nice and is simple to follow.Wrapping up
The bottom line is that these NOSes tender a wide sweep of characteristics and provide enterprise customers with a much deal of preference regarding how each can exist used in any given corporate network.
If you want a good, generic purpose NOS that can deliver enterprise-class services with All the bells and whistles imaginable, then Windows 2000 is the strongest contender. However, for high performance, enterprise file and print services, their tests reveal that Novell leads the pack. If you're willing to pay a higher charge for scalability and reliability, SCO UnixWare would exist a safe bet. But if you need an inexpensive alternative that will give you bare-bones network services with decent performance, Red Hat Linux can certainly suitable the bill.
The preference is yours.
Bass is the technical director and Robinson is a senior technical staff member at Centennial Networking Labs (CNL) at North Carolina situation University in Raleigh. CNL focuses on performance, capacity and features of networking and server technologies and equipment.RELATED STORIES:
Debate will focus on Linux vs. LinuxJanuary 20, 2000Some Windows 2000 PCs will jump the gunJanuary 19, 2000IBM throws Linux lovefestJanuary 19, 2000Corel Linux will dash Windows appsJanuary 10, 2000Novell's eDirectory spans platformsNovember 16, 1999New NetWare embraces Web appsNovember 2, 1999Microsoft sets a date for Windows 2000October 28, 1999RELATED IDG.net STORIES:
Fusion's Forum: Square off with the vendors over who has the best NOS(Network World Fusion)How they did it: Details of the testing(Network World Fusion)Find out the tuning parameters(Network World Fusion)Download the Config files(Network World Fusion)The Shootout results(Network World Fusion)Fusion's NOS resources(Network World Fusion)With Windows 2000, NT grows up(Network World Fusion)Fireworks expected at NOS showdown(Network World Fusion)
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Novell, Inc.Microsoft Corp.The Santa Cruz Operation, Inc. (SCO)Red Hat, Inc.
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ActiveBatch Gets Blackberry Functionality
Administrators occupy long been able to receive pages when servers retract down, but now they can restart servers with their pagers. Advanced Systems Concepts Inc. has added the Blackberry line of pagers to its list of clients for the ActiveBatch Job Scheduling and Management System.
The ActiveBatch Wireless Client is a module for the management software that enables administrators to monitor systems and initiate processes from the Blackberry. ActiveBatch Job Scheduling and Management System allows users to set up calendars to initiate processes such as backups or printing, or initiate processes from remote clients.
Ben Rosenberg, CEO of Advanced Systems, says the company chose to advocate the Blackberry first since it was the handheld best suited for round-the-clock monitoring. "The battery life is three weeks, and it’s always on," he says. Advanced Systems supports both the pager-sized and PDA-sized Blackberries.
If a system sends out an SNMP signal, administrators can configure the system to ship an e-mail to a Blackberry, alerting the administrator. The e-mail gives the administrator the option to initiate processes, such as rebooting a server, through the Blackberry. "With the Blackberry, e-mails are always actionable by you," Rosenberg says.
Rosenberg sees two advantages to system management through wireless devices. First, it obviates the need to give instructions over the phone to a less experienced operator. Second, high-level administrators who travel can withhold an eye on the system. "If you’re on the road, you’re able to know if something is wrong," he says. With both advantages, administrators will exist better able to guarantee uptime, with less impact on their lives.
In addition to the three levels of encryption standards on Blackberry devices, ActiveBatch provides additional security features, such as a password login to the system. This keeps random users, including thieves, from wreaking havoc on corporate systems. "Use of ActiveBatch is always secure," Rosenberg says.
ActiveBatch can manage Windows, OpenVMS and Unix-based systems with an agent on each server. The agent sends information to a central Windows console. The software integrates with the Windows Management Instrument, which furthermore serves as a SNMP provider. ActiveBatch provides three plug-ins for remote clients: e-mail, browser and now the Blackberry.
Rosenberg says Advanced Systems is working to bring ActiveBatch to PocketPC handhelds. He says that although users can already exercise them with the browser-based system, the company will adapt the system to better meet the needs and limitations of the PocketPC platform.
Contact: Advanced Systems Concepts Inc., www.advsyscon.com, (201) 798-6400
SafeStone Provides iSeries advocate to RSA Security
Security management provider SafeStone Technologies plc. has added iSeries 400 features to an existing partnership with RSA Security Inc. Under the enhanced agreement, SafeStone is making RSA’s SecurID authentication utensil usable on an iSeries 400 platform.
Using its DetectIT Agent 400 interface, SafeStone is enabling two-factor authentication. Two-factor authentication requires an individual to exist verified twice before access is allowed to systems.
DetectIT is an offering designed by SafeStone to protect iSeries 400 exit points from unauthorized user access to confidential data, application and resources within an open-connectivity environment.
Through DetectIT, RSA’s iSeries-based users will exist able to leverage software solutions for auditing, data and system management, e-business security, and application and access control for lone or multiple networked iSeries 400s.
As Part of its agreement with RSA, SafeStone will act as RSA’s IBM iSeries industry partner, handling All sales and advocate responsibility for DetectIT. In this role, SafeStone, which is furthermore an IBM ally for systems management and development, will tender DetectIT to RSA’s customers as either a standalone or fully integrated offering.
Contact: RSA Security, Inc., www.rsa.com, (781) 301-5000
SafeStone Technologies plc, www.safestone.com
Vendors originate Linux Itanium-Ready
With Intel Corp.’s May release of its 64-bit Itanium processor, Linux vendors are lining up to advocate the current architecture. Red Hat Inc., TurboLinux Inc., SuSE AG and Caldera International Inc. All formally released distributions for Itanium.
To coincide with the announcement, TurboLinux released its Operating System 7 for the Itanium processor. "It’s production-ready," says Thrane Jensen, product manager for Itanium. However, Jensen admits that many users will exercise early Itanium machines for testing and development, rather than using them in production environments yet.
Bill Claybrook, research director for Linux and open source at the Aberdeen Group, confirms that "most people are waiting for McKinley." He believes that users will wait for Intel to release McKinley—its second-generation IA-64 processor—before they integrate IA-64 into their environments. "They’re being a miniature bit leery of it [in] a production environment," he says. Jensen says TurboLinux is working on its McKinley version of Linux already.
Jensen says that porting Linux to the IA-64 processor had its challenges. The 64-bit nature of the processor created challenging issues for stirring applications over to the current chip. "Dependencies on 32-bit create problems," he says. Some applications addressed specific 32-bit features that did not exist in Itanium. For the most part, applications could exist recompiled for the chip. "In general, it’s along the very code line," he says, "but the kernel has [alot of] different stuff."
In addition to the core operating system, Jensen says many common Linux applications are furthermore ready for prime time. Apache and other commonly used applications are production-ready, but "ISVs are going to exist doing more application development," he says.
Red Hat released its Red Hat Linux 7.1 for the Itanium processor in mid-June. Using the 2.4 kernel, Red Hat positions the current release as a platform for testing 64-bit applications ported from 32-bit and RISC machines. The distribution is furthermore suited to enterprise server needs; it runs on up to eight processors and offers current configuration tools for BIND, Apache and printing.
At the very time, Linux vendor SuSE released an Itanium-specific distribution. SuSE Linux 7.2 for IA-64 uses six CD-ROMs to carry over 1,500 applications for the emerging platform. enjoy Red Hat, the company bills the package as a solution for evaluating and deploying Itanium-based servers.
Although a preview version was already available from the Caldera FTP site at ftp.caldera.com/ia64, Caldera released two current versions in May, accompanied by a public announcement. The final production version of OpenLinux Server 64 should exist available late in the third quarter.
Biff Traber, senior vice president and generic manager of the server industry line at Caldera, says Caldera has miniature to lose by waiting to release a production version. Customers will Look to the distribution for evaluation purposes, so a beta release meets their needs. "It’s a combination of testing, progress and prototyping," he says.
The Trillian project, which initiated progress of a Linux kernel for the Itanium processor, first released a kernel in February 2000, predating Itanium’s generic availability by over a year. Intel was aggressive in getting prototype chips to developers to ensure a market providing hardware, remote servers and emulators to enable open source developers to occupy Linux ready for the release date.
The project later changed its designation to the more formal-sounding IA-64 Linux Project and worked to further enhance the progress of Linux on Itanium. Itanium is not the first 64-bit platform to dash Linux—there were already flavors of Linux for Sun Microsystems Inc.’s Sparc processor and Compaq Computer Corp.’s Alpha. In addition to the distributors, the IA-64 Linux Project furthermore boasted hardware vendors, Hewlett-Packard Co., IBM Corp., Silicon Graphics Inc., VA Linux Systems Inc. and NEC Corp., as well as Intel and Swiss research laboratory CERN.
If they consider filesystems as a mechanism for both storing and locating data, then the two key elements for any filesystem are the items being stored and the list of where those items are. The deeper details of how a given filesystem manipulates its data and meta-information retract beyond the scope of this chapter but are addressed further in Appendix B, "Anatomy of a Filesystem."Filesystem Components That the Admin Needs to Know About
As always, they need to rep a wield on the vocabulary before they can understand how the elements of a filesystem labor together. The next three sections picture the basic components with which you, as a sysadmin, need to exist familiar.Files
The most intuitively obvious components of a filesystem are, of course, its files. Because everything in UNIX is a file, special functions are differentiated by file type. There are fewer file types than you might imagine, as Table 3.2 shows.Table 3.2 File Types and Purposes, with Examples
Maintains information for directory structure
Buffered device file
Raw device file
UNIX domain socket
Interprocess communication (IPC)
See output of commands for files Linux: netstat –x Solaris: netstat -f unix
Named pipe special (FIFO device)
First-in-first-out IPC mechanism, Invoked by name
Linux: /dev/initctl Solaris: /etc/utmppipe/etc/cron.d/FIFO
Pointer to another file (any type)
/usr/tmp -> ../var/tmp
All other files; holds data of All other types
Text files expostulate files Database files Executables/binaries
Notice that directories are a character of file. The key is that they occupy a specific character of format and contents (see Appendix B for more details). A directory holds the filenames and index numbers (see the following section, "Inodes") of All its constituent files, including subdirectories.
Directory files are not flat (or regular) files, but are indexed (like a database), so that you can silent locate a file quickly when you occupy a big number of files in the very directory.13
Even though file handling is generally transparent, it is considerable to recall that a file's data blocks14 may not exist stored sequentially (or even in the very generic disk region). When data blocks are widely scattered in an uncoordinated manner, it can finger access times and increase I/O overhead.Inodes
Meta-information about files is stored in structures called index nodes, or inodes. Their contents vary based on the particular filesystem in use, but All inodes hold the following information about the file they index:15
Inode identification number
Owners: user and group
ctime: eventual file status change time
mtime: eventual data modification time16
atime: eventual access time
Physical location information for data blocks
Notice that the filename is not stored in the inode, but as an entry in the file's closest parent directory.
All other information about a file that ls displays is stored in an inode somewhere. With a few handy options, you can haul out lots of useful information. Let's verbalize that you want to know the inode number of the Solaris kernel.17 You just give the –i option, and voilá:
[sun:10 ~]ls -i /kernel/genunix
Of course, ls –l is an dilapidated friend, telling you most everything that you want to know. Looking at the Solaris kernel again, you rep the output in figure 3.4.
Figure 3.4 Diagrammed Output of ls on a File
Notice that the timestamp shown by default in a long listing is mtime. You can pass various options to ls to view ctime and atime instead. For other nifty permutations, descry the ls man page.
File Permissions and Ownership Refresher
Because UNIX was designed to advocate many users, the question naturally arises how to know who can descry what files. The first and simplest retort is simply to permit users to examine only their own files. This, of course, would originate it difficult, if not impossible, to share, creating much difficulties in collaborative environments and causing a string of other problems: Why can't I dash ls? Because the system created it, not you, is only the most obvious specimen of such problems.
Users and Groups
UNIX uses a three-part system to determine file access: There's what you, as the file owner, are allowed to do; there's what the group is allowed to do; and there's what other people are allowed to do. Let's descry what Elvis's permissions Look like:
[ elvis@frogbog elvis ]$ ls -l
drwxr-xr-x 5 elvis users 4096 Dec 9 21:55 Desktop
drwxr-xr-x 2 elvis users 4096 Dec 9 22:00 Mail
-rw-r--r-- 1 elvis users 36 Dec 9 22:00 README
-rw-r--r-- 1 elvis users 22 Dec 9 21:59 ThisFile
drwxr-xr-x 2 elvis users 4096 Dec 12 19:57 arc
drwxr-xr-x 2 elvis users 4096 Dec 10 00:40 songs
-rw-r--r-- 1 elvis users 46 Dec 12 19:52 tao.txt
-rw-r--r-- 1 elvis users 21 Dec 9 21:59 thisfile
-rw-r--r-- 1 elvis users 45 Dec 12 19:52 west.txt
As long as we're here, let's crash down exactly what's being displayed. First, they occupy a 10-character string of letters and hyphens. This is the representation of permissions, which I'll crash down in a minute. The second item is a number, usually a lone digit. This is the number of arduous links to that directory. I'll debate this later in this chapter. The third thing is the username of the file owner, and the fourth is the designation of the file's group. The fifth column is a number representing the size of the file, in bytes. The sixth contains the date and time of eventual modification for the file, and the final column shows the filename.
Every user on the system has a username and a number that is associated with that user. This number generally is referred to as the UID, short for user ID. If a user has been deleted but, for some reason, his files remain, the username is replaced with that user's UID. Similarly, if a group is deleted but silent owns files, the GID (group number) shows up instead of a designation in the group field. There are furthermore other circumstances in which the system can't correlate the designation and the number, but these should exist relatively rare occurrences.
As a user, you can't change the owner of your files: This would open up some staid security holes on the system. Only root can chown files, but if he makes a mistake, you can now examine root to chown the files to you. As a user, you can chgrp a file to a different group of which you are a member. That is, if Elvis is a member of a group named users and a group named elvis, he can chgrp elvis west.txt or chgrp users west.txt, but because he's not a member of the group beatles, he can't chgrp beatles west.txt. A user can belong to any number of groups. Generally (although this varies quite by flavor), files created belong to the group to which the directory belongs. On most modern UNIX variants, the group that owns files is whatever group is listed as your primary group by the system in the /etc/passwd file and can exist changed via the newgrp command. On these systems, Elvis can chgrp users if he wants his files to belong to the users group, or he can chgrp elvis if he wants his files to belong to the elvis group.
So, what were those droll strings of letters and hyphens at the rise of each long directory listing? I already said that they represented the permissions of the file, but that's not especially helpful. The 10 characters of that string depict the authorization bits for each file. The first character is separate, and the eventual nine are three very similar groups of three characters. I'll interpret each of these in turn.
If you Look back to Elvis's long listing of his directory, you'll descry that most of the files simply occupy a hyphen as the first character, whereas several possess a d in this field. The more astute reader might note that the files with a d in that first domain All betide to exist directories. There's a wonderful judgement for this: The first permissions character denotes whether that file is a special file of one sort or another.
What's a special file? It's either something that isn't really a file (in the sense of a sequential stream of bytes on a disk) but that UNIX treats as a file, such as a disk or a video display, or something that is really a file but that is treated differently. A directory, by necessity, is a stream of bytes on disk, but that d means that it's treated differently.
The next three characters depict what the user who owns the file can carry out with it. From left to right, these permissions are read, write, and execute. Read authorization is just that—the capability to descry the contents of a file. Write authorization implies not only the right to change the contents of a file, but furthermore the right to delete it. If I carry out not possess write authorization to a file, rm not_ permitted.txt fails.
Execute authorization determines whether the file is furthermore a command that can exist dash on the system. Because UNIX sees everything as a file, All commands are stored in files that can exist created, modified, and deleted enjoy any other file. The computer then needs a course to show what can and can't exist run. The execute bit does this.
Another considerable judgement that you need to worry about whether a file is executable is that some programs are designed to exist dash only by the system administrator: These programs can modify the computer's configuration or can exist hazardous in some other way. Because UNIX enables you to specify permissions for the owner, the group, and other users, the execute bit enables the administrator to restrict the exercise of hazardous programs.
Directories deal the execute authorization differently. If a directory does not occupy execute permissions, that user (or group, or other users on the system) can't cd into that directory and can't Look at information about the files in that directory. (You usually can find the names of the files, however.) Even if you occupy permissions for the files in that directory, you generally can't Look at them. (This varies quite by platform.)
The second set of three characters is the group permissions (read, write, and execute, in that order), and the final set of three characters is what other users on the system are permitted to carry out with that file. Because of security concerns (either due to other users on your system or due to pervasive networks such as the Internet), giving write access to other users is highly discouraged.
Great, you can now read the permissions in the directory listing, but what can you carry out with them? Let's verbalize that Elvis wants to originate his directory readable only by himself. He can chmod go-rwx ~/songs: That means remove the read, write, and execute permissions for the group and others on the system. If Elvis decides to let Nashville artists remove a Look at his material but not change it (and if there's a group nashville on the system), he can first chgrp nashville songs and then chmod g+r songs.
If Elvis does this, however, he'll find that (at least, on some platforms) members of group nashville can't Look at them. Oops! With a simple chmod g+x songs, the problem is solved:
[ elvis@frogbog elvis ]$ ls -l
drwxr-xr-x 5 elvis users 4096 Dec 9 21:55 Desktop
drwxr-xr-x 2 elvis users 4096 Dec 9 22:00 Mail
-rw-r--r-- 1 elvis users 36 Dec 9 22:00 README
-rw-r--r-- 1 elvis users 22 Dec 9 21:59 ThisFile
drwxr-xr-x 2 elvis users 4096 Dec 12 19:57 arc
drwxr-x--- 2 elvis nashvill 4096 Dec 15 14:21 songs
-rw-r--r-- 1 elvis users 46 Dec 12 19:52 tao.txt
-rw-r--r-- 1 elvis users 21 Dec 9 21:59 thisfile
-rw-r--r-- 1 elvis users 45 Dec 12 19:52 west.txt
In addition to the read, write, and execute bits, there exists special permissions used by the system to determine how and when to suspend the regular authorization rules. Any thorough understanding of UNIX requires an understanding of the setuid, setgid, and sticky bits. For regular system users, only a generic understanding of these is necessary, and this discussion is thus brief. wonderful documentation on this subject exists elsewhere for budding system administrators and programmers.
The setuid bit applies only to executable files and directories. In the case of executable programs, it means that the given program runs as though the file owner were running it. That is, xhextris, a variant on Tetris, has the following permissions on my system:
1 games games 32516 May 18 1999 /usr/X11R6/bin/xhextris
There's a pseudouser called games on the system, which can't exist logged into and has no home directory. When the xhextris program executes, it can read and write to files that only the game's pseudouser normally would exist permitted. In this case, there's a high-score file stored on the system that writeable only by that user. When Elvis runs the game, the system acts as though he were the user games, and thus he is able to store the high-score file. To set the setuid bit on a file, you can show chmod to give it mode u+s. (You can mediate of this as uid set, although this isn't technically accurate.)
The setgid bit, which stands for "set group id," works almost identically to setuid, except that the system acts as though the user's group is that of the given file. If xhextris had used setgid games instead of setuid games, the high score would exist writeable to any directory owned by the group games. It is used by the system administrator in ways fundamentally similar to the setuid permission.
When applied to directories on Linux, Irix, and Solaris (and probably most other POSIX-compliant UNIX flavors as well), the setgid bit means that current files are given the parent directory's group rather than the user's primary or current group. This can exist useful for, say, a directory for fonts built by (and for) a given program. Any user might generate the fonts via a setgid command that writes to a setgid directory. setgid on directories varies by platform; check your documentation. To set the setgid bit, you can show chmod to exercise g+s (gid set).
Although a file in a group or world-writeable directory without the sticky bit can exist deleted by anyone with write authorization for that directory (user, group, or other), a file in a directory with the sticky bit set can exist deleted only by either the file's owner or root. This is particularly useful for creating temporary directories or scratch space that can exist used by anyone without one's files being deleted by others. You can set authorization +t in chmod to give something the sticky bit.
Like almost everything else on UNIX, permissions occupy a number associated with them. It's generally considered that permissions are a group of four digits, each between 0 and 7. Each of those digits represents a group of three permissions, each of which is a yes/no answer. From left to right, those digits depict special permissions, user permissions, group permissions, and other permissions.
So, About Those authorization Bits...
Most programs reading authorization bits anticipate four digits, although often only three are given. Shorter numbers are filled in with leading zeros: 222 is treated as 0222, and 5 is treated as 0005. The three rightmost digits are, as previously mentioned, user (owner) permissions, group permissions, and other permissions, from right to left.
Each of these digits is calculated in the following manner: read authorization has a value of 4, write authorization has a value of 2, and execute authorization has a value of 1. Simply add these values together, and you've got that authorization value. Read, write, and execute would exist 7, read and write without execute would exist 6, and no authorization to carry out anything would exist 0. Read, write, and execute for the file owner, with read and execute for the group and nothing at All for anyone else, would exist 750. Read and write for the user and group, but only read for others, would exist 664.
The special permissions are 4 for setuid, 2 for setgid, and 1 for sticky. This digit is prepended to the three-digit numeric permission: A temporary directory with sticky read, write, and execute authorization for everyone would exist mode 1777. A setuid root directory writeable by nobody else would exist 4700. You can exercise chmod to set numeric permissions directly, as in chmod 1777 /tmp.
In addition to a more precise exercise of chmod, numeric permissions are used with the umask command, which sets the default permissions. More precisely, it "masks" the default permissions: The umask value is subtracted from the maximum workable settings.* umask deals only with the three-digit permission, not the full-fledged four-digit value. A umask of 002 or 022 is most commonly the default. 022, subtracted from 777, is 755: read, write, and execute for the user, and read and execute for the group and others. 002 from 777 is 775: read, write, and execute for the user and group, and read and execute for others. I minister to set my umask to 077: read, write, and execute for myself, and nothing for my group or others. (Of course, when working on a group project, I set my umask to 007: My group and I can read, write, or execute anything, but others can't carry out anything with their files.)
You should note that the umask assumes that the execute bit on the file will exist set. All umasks are subtracted from 777 rather than 666, and those extra ones are subtracted later, if necessary. (See Appendix B for more details on authorization bits and umask workings.)
*Actually, the authorization bits are XORed with the maximum workable settings, if you're a computer science type.
Also notice that the first bit of output prepended to the permissions string indicates the file type. This is one handy course of identifying a file's type. Another is the file command, as shown in Table 3.3.Table 3.3 ls File Types and file Output Sample
ls File character Character
File panoply Example
[either:1 ~]file /usr/usr: directory
Block special device
[linux: 10 ~] file /dev/hda1/dev/hda1: screen special (3/1)[sun:10 root ~]file /dev/dsk/c0t0d0s0/dev/dsk/c0t0d0s0: screen special(136/0)
Character special device
[linux:11 ~] file /dev/tty0/dev/tty0: character special (4/0)
[ensis:11 ~]file /dev/rdsk/c0t0d0s0/dev/rdsk/c0t0d0s0: character special (136/0)
UNIX domain socket
[linux:12 ~] file /dev/log/dev/log: socket
[sun:12 ~]file /dev/ccv/dev/ccv: socket
Named pipe special (FIFO device)
[linux:13 ~] file /dev/initctl/dev/initctl: fifo (named pipe)
[sun:13 ~]file /etc/utmppipe/etc/utmppipe: fifo
[linux:14 ~] file /usr/tmp/usr/tmp: symbolic link to ../var/tmp
[sun:14 ~]file -h /usr/tmp/usr/tmp: symbolic link to ¬../var/tmp
[linux:15 ~] file /etc/passwd/etc/passwd: ASCII text
[linux:15 ~] file /boot/vmlinux-2.4.2-2/boot/vmlinux-2.4.2-2: ELF 32-bit LSB executable,
¬Intel 80386, version 1,statically linked, not stripped
[linux:15 ~] file /etc/rc.d/init.d/sshd/etc/rc.d/init.d/sshd: Bourne-Again shell script text executable
[sun:15 ~]file /etc/passwd
/etc/passwd: ascii text
[sun:15 ~]file /kernel/genunix
-/kernel/genunix: ELF 32-bit MSB relocatable
¬SPARC Version 1
[sun:15 ~]file /etc/init.d/sshd
Notice the in-depth information that file gives—in many cases, it shows details about the file that no other command will readily panoply (such as what benevolent of executable the file is). These low-level details are beyond the scope of their discussion, but the man page has more information.
Important Points about the file ommand
file tries to figure out what character a file is based on three types of test:
The file character that the ls –l command returns.
-The presence of a magic number at the rise of the file identifying the file type. These numbers are defined in the file /usr/share/magic in Red Hat Linux 7.1 and /usr/lib/locale/locale/LC_MESSAGES/magic (or /etc/magic) in Solaris 8. Typically, only binary files will occupy magic numbers.
-In the case of a regular/text file, the first few bytes are tested to determine the character of text representation and then to determine whether the file has a recognized purpose, such as C code or a Perl script.
file actually opens the file and changes the atime in the inode.
Inode lists are maintained by the filesystem itself, including which ones are free for use. Inode allocation and manipulation is All transparent to both sysadmins and users.
Inodes become significant at two times for the sysadmin: at filesystem creation time and when the filesystem runs out of free inodes. At filesystem creation time, the total number of inodes for the filesystem is allocated. Although they are not in use, space is set aside for them. You cannot add any more inodes to a filesystem after it has been created. When you dash out of inodes, you must either free some up (by deleting or stirring files) or migrate to another, larger filesystem.
Without inodes, files are just a random assortment of ones and zeros on the disk. There is no guarantee that the file will exist stored sequentially within a sector or track, so without an inode to point the course to the data blocks, the file is lost. In fact, every file is uniquely identified by the combination of its filesystem designation and inode number.
See Appendix B for more detailed information on the exact content of inodes and their structure.
Linux has a very useful command called stat that dumps the contents of an inode in a tidy format:[linux:9 ~]stat . File: "." Size: 16384 Filetype: Directory Mode: (0755/drwxr-xr-x) Uid: (19529/ robin) Gid:(20/users) Device: 0,4 Inode: 153288707 Links: 78 Access: Sun Jul 22 13:58:29 2001(00009.04:37:59) Modify: Sun Jul 22 13:58:29 2001(00009.04:37:59) Change: Sun Jul 22 13:58:29 2001(00009.04:37:59) Boot screen and Superblock
When a filesystem is created, two structures are automatically created, whether they are immediately used or not. The first is called the boot block, where boot-time information is stored. Because a partition may exist made bootable at will, this structure needs to exist available at All times.
The other structure, of more interest here, is the superblock. Just as an inode contains meta-information about a file, a superblock contains metainformation about a filesystem. Some of the more captious contents are listed here:18
Timestamp: eventual update
Superblock situation flag
Filesystem situation flag: clean, stable, active
Number of free blocks
List of free blocks
Pointer to next free block
Size of inode list
Number of free inodes
List of free inodes
Pointer to next free inode
Lock fields for free blocks and inodes
Summary data block
And you thought inodes were complex.
The superblock keeps track of free file blocks and free inodes so that the filesystem can store current files. Without these lists and pointers, a long, sequential search would occupy to exist performed to find free space every time a file was created.
In much the very course that files without inodes are lost, filesystems without intact superblocks are inaccessible. That's why there is a superblock situation flag—to bespeak whether the superblock was properly and completely updated before the disk (or system) was eventual taken offline. If it was not, then a consistency check must exist performed for the total filesystem and the results stored back in the superblock.
Again, more detailed information about the superblock and its role in UNIX filesystems may exist institute in Appendix B.Filesystem Types
Both Red Hat and Solaris recognize a host of different filesystem types, although you will generally finish up using and supporting just a few. There are three gauge types of filesystem—local, network, and pseudo—and a fourth "super-filesystem" character that is actually losing ground, given the size of modern disks.Local Filesystems
Local filesystems are common to every system that has its own local disk.19 Although there are many instances of this character of filesystem, they are All designed to labor within a system, managing the components discussed in the eventual section and interfacing with the physical drive(s).
Only a few local filesystems are specifically designed to exist cross-platform (and sometimes even cross–OS-type). They compass in handy, though, when you occupy a nondisk hardware failure; you can just remove the disk and withhold it into another machine to retrieve the data.20 The UNIX File System, or ufs, was designed for this; both Solaris and Red Hat Linux machines can exercise disks with this filesystem. Note that Solaris uses ufs filesystems by default. Red Hat's default local filesystem is ext2.
Another local, cross-platform filesystem is ISO9660, the CD-ROM standard. This is why you can read your Solaris CD in a Red Hat box's reader.
Local filesystems compass in two related but several flavors. The original, gauge model filesystem is silent in broad exercise today. The newer journaling filesystem character is just rise to really compass into its own. The major inequity between the two types is the course they track changes and carry out integrity checks.Standard Filesystems
Standard, nonjournaling filesystems depend on flags in the superblock for consistency regulation. If the superblock flag is not set to "clean," then the filesystem knows that it was not shut down properly: not All write buffers were flushed to disk, and so on. Inconsistency in a filesystem means that allocated inodes could exist overwritten; free inodes could exist counted as in use—in short, rampant file corruption, mass hysteria.
But there is a filesystem integrity checker to rescue the day: fsck. This command is usually invoked automatically at boot-time to verify that All filesystems are clean and stable. If the / or /usr filesystems are inconsistent, the system might prompt you to start up a miniroot shell and manually dash fsck. A few of the more captious items checked and corrected are listed here:
Unclaimed blocks and inodes (not in free list or in use)
Unreferenced but allocated blocks and inodes
Multiply claimed blocks and inodes
Bad inode formats
Bad directory formats
Bad free screen or inode list formats
Incorrect free screen or inode counts
Superblock counts and flags
Note that a filesystem should exist unmounted before running fsck (see the later section "Administering Local Filesystems"). Running fsck on a mounted filesystem might occasions a system panic and crash, or it might simply decline to dash at all. It's furthermore best, though not required, that you dash fsck on the raw device, when possible. descry the man page for more details and options.
So where does fsck withhold orphans, the blocks and inodes that are clearly in exercise but aren't referenced anywhere? Enter the lost+found directories. There is always a /lost+found directory on every system; other directories accrue them as fsck finds orphans in their purview. fsck automatically creates the directories as needed and renames the lost blocks into there by inode number. descry the man pages "mklost+found" on Red Hat and "fsck_ufs" on Solaris.Journaling Filesystems
Journaling filesystems carry out away with fsck and its concomitant superblock structures. All filesystem situation information is internally tracked and monitored, in much the very course that databases systems set up checkpoints and self-verifications.
With journaling filesystems, you occupy a better haphazard of plenary data recovery in the event of a system crash. Even unsaved data in buffers can exist recovered thanks to the internal log.21 This benevolent of fault tolerance makes journaling filesystems useful in high- availability environments.
The drawback, of course, is that when a filesystem enjoy this gets corrupted somehow, it presents major difficulties for recovery. Most journaling filesystems provide their own salvaging programs for exercise in case of emergency. This underscores how captious backups are, no matter what benevolent of filesystem software you've invested in. descry Chapter 16, "Backups," for more information.
One of the earliest journaling filesystems is silent a commercial venture: VxFS by Veritas. Another pioneer has decided to release its software into the public domain under GPL22 licensing: JFS23 by IBM. SGI's xfs journaling filesystem has been freely available under GPL since about 1999, although it is only designed to labor under IRIX and Linux.24
Maintenance of filesystem situation incurs an overhead when using journaling filesystems. As a result, these filesystems accomplish suboptimally for minuscule filesystem sizes. Generally, journaling filesystems are arrogate for filesystem sizes of 500Mb or more.Network Filesystems
Network-based filesystems are really add-ons to local filesystems because the file server must occupy the actual data stored in one of its own local filesystems.25 Network file- systems occupy both a server and client program.
The server usually runs as a daemon on the system that is sharing disk space. The server's local filesystems are unaffected by this extra process. In fact, the daemon generally only puts a few messages in the syslog and is otherwise only visible through ps.
The system that wants to access the server's disk space runs the client program to mount the shared filesystems across the network. The client program handles All the I/O so that the network filesystem behaves just a enjoy a local filesystem toward the client machine.
The dilapidated standby for network-based filesystems is the Network File System (NFS). The NFS gauge is currently up to revision 3, though there are quite a number of implementations with their own version numbers. Both Red Hat and Solaris compass gauge with NFS client and server packages. For more details on the inner workings and configuration of NFS, descry Chapter 13, "File Sharing."
Other network-based filesystems comprehend AFS (IBM's Andrew File System) and DFS/DCE (Distributed File System, Part of the Open Group's Distributed Computing Environment). The mechanisms of these advanced filesystems retract beyond the scope of this book, although their goal is silent the same: to efficiently share files across the network transparently to the user.Pseudo Filesystems
Pseudofilesystems are an provocative progress in that they are not actually related to disk-based partitions. They are instead purely ratiocinative constructs that depict information and meta-information in a hierarchical structure. Because of this structure and because they can exist manipulated with the mount command, they are silent referred to as filesystems.
The best specimen of pseudofilesystems exists on both Red Hat and Solaris systems: /proc. Under Solaris, /proc is restricted to just managing process information:[sun:1 ~]ls /proc 0 145 162 195 206 230 262 265 272 286 299 303 342 370 403 408 _672 752 1 155 185 198 214 243 263 266 278 292 3 318 360 371 404 52 _674 142 157 192 2 224 252 264 268 280 298 302 319 364 400 406 58 _678
Note that these directories are All named according to the process numbers corresponding to what you would find in the output of ps. The contents of each directory are the various meta-information that the system needs to manage the process.
Under Red Hat, /proc provides information about processes as well as about various system components and statistics:[linux:1 ~] ls /proc 1 18767 23156 24484 25567 28163 4 493 674 8453 ksyms _stat 13557 18933 23157 24486 25600 3 405 5 675 9833 loadavg _swaps 13560 18934 23158 24487 25602 3050 418 5037 676 9834 locks _sys 13561 18937 23180 24512 25603 3051 427 5038 7386 9835 mdstat _tty 1647 19709 23902 24541 25771 3052 441 5054 7387 bus meminfo _uptime 1648 19730 23903 24775 25772 30709 455 5082 7388 cmdline misc _version 1649 19732 23936 25494 25773 30710 473 510 7414 cpuinfo modules 16553 19733 24118 25503 25824 30712 485 5101 7636 devices mounts 18658 2 24119 25504 25882 30729 486 524 7637 dma mtrr 18660 21450 24120 25527 25920 320 487 558 7638 filesystems net 18661 21462 24144 25533 26070 335 488 6 7662 fs _partitions 18684 21866 24274 25534 26071 337 489 670 8426 interrupts pci 18685 21869 24276 25541 26072 338 490 671 8427 ioports scsi 18686 21870 24277 25542 28161 339 491 672 8428 kcore self 18691 21954 24458 25543 28162 365 492 673 8429 kmsg slabinfo
Again they descry the directories named for process numbers, but they furthermore descry directories with indicative names such as cpuinfo and loadavg. Because this is a hierarchical filesystem, you can cd into these directories and read the various files for their system information.
The most provocative thing about /proc is that it allows even processes to exist treated enjoy files.26 This means that pretty much everything in UNIX, whether it is something that just exists or something that actually happens, can now exist considered a file.
For more information under Red Hat, character man proc. For more information under Solaris, character man –s 4 proc.Logical Volumes
Finally, there are the "super-filesystems" or ratiocinative volumes that carry out what the other major types of filesystem cannot: surmount the barriers of partitions. You may well examine why anyone would want to carry out that. There are two reasons. First, because disks used to exist a lot smaller and more costly, you used what you had at hand. If you needed a big pool of disk space, ratiocinative volumes allowed you to aggregate remnants into something useable. Second, even with larger disks, you silent might not exist able to achieve the benevolent of disk space required by a particular researcher or program. Once again, ratiocinative volumes allow you to aggregate partitions across disks to profile one big filesystem.
Crossing disk boundaries with a ratiocinative volume is referred to as disk spanning. Once you occupy ratiocinative volumes, you can furthermore occupy some fairly knotty data management methods and performance-enhancing techniques. Disk striping, for example, is a performance booster. Instead of sequentially filling one disk and then the next in series, it spreads the data in discrete chunks across disks, allowing better I/O response through parallel operations.
RAID27 implements ratiocinative volumes at 10 several levels, with various features at each level. This implementation can exist done either in hardware or in software, although the nomenclature for both is the same.28Table 3.4 RAID Levels
-Requires extra drives for data duplication
(Very similar to RAID-3)
Requires part parity disk
Requires part parity disk
(Very similar to RAID-5)
Slowest for writes, but
Rotating parity array
good for reads
Requires three to five part parity disks
Reconstruction by parity data (not duplication)
RAID-5 + secondary
Not in broad use
RAID-5 + real-time embedded controller
Not in broad use
-RAID-0 array duplicated (mirrored)
-Each stripe is RAID-1 (mirrored) array
Array of parity stripes
Each stripe is RAID-3 array
Clearly, the benevolent of complexity inherent in All ratiocinative volume systems requires some benevolent of back-end management system. Red Hat offers the ratiocinative Volume Manager (LVM) as a kernel module. While the details of LVM are beyond the scope of this book, it is provocative to note that you can withhold any filesystem that you want on top of the ratiocinative volume. Start at http://www.linuxdoc.org/HOWTO/LVM-HOWTO.htmlfor more details.
Although Sun offers ratiocinative volume management, it is through a for-pay program called "Solstice DiskSuite." The filesystem on DiskSuite ratiocinative volumes must exist ufs. For more information, start at http://docs.sun.com/ab2/coll.260.2/DISKSUITEREF.
Another commercial ratiocinative volume manager for Solaris comes from Veritas; see: http://www.veritas.com/us/products/volumemanager/faq.html#a24
The beauty of All ratiocinative volumes is that they issue to exist just another local filesystem and are completely transparent to the user. However, ratiocinative volumes carry out add some complexity for the systems administrator, and the schema should exist carefully documented on paper, in case it needs to exist re-created.NAS
Normally, a file server's disks are directly attached to the file server. With network-attached storage (NAS), the file server and the disks that it serves are part entities, communicating over the local network. The storage disks require an aggregate controller that arbitrates file I/O requests from the external server(s). The server(s) and the aggregate controller each occupy several network IP addresses. To serve the files to clients, a file (or application) server sends file I/O requests to the NAS aggregate controller and relays the results back to client systems.
NAS is touched on here for completeness—entire books can exist written about NAS design and implementation. NAS does not really depict a character of filesystem, but rather it is a mechanism to relieve the file server from the details of hardware disk access by isolating them in the network-attached storage unit.Red Hat Filesystem Reference Table
Table 3.5 lists major filesystems that currently advocate (or are supported by) Red Hat.29 The filesystem types that are currently natively supported are listed in /usr/src/linux/ fs/filesytems.c.Table 3.5 Filesystem Types and Purposes, with Examples (Red Hat)
Specific Instances (as Used in /etc/fstab)
Red Hat default filesystem
Journaling filesystem from IBM
Journaling filesystem from SGI
Windows compatibility: DOS
Windows compatibility: NT
Windows compatibility: FAT-32
Adfs hfs romfs
Affs hpfs smbfs
Coda mnix udf
devpts ncpfs umsdos
Deprecated, pre-kernel 2.1.21
Network-based remote communication
Store process (and other system) meta-informationSolaris Filesystem Reference Table
Table 3.6 lists major filesystems that currently advocate (or are supported by) Solaris. The filesystem types that currently are natively supported are listed as directories under /usr/lib/fs.Table 3.6 Filesystem Types and Purposes, with Examples (Solaris)
Specific Instances (as Used in /etc/vfstab)
Solaris default filesystem; Red Hat-compatible
Journaling filesystem from IBM
Network-based remote communication
Store process metainformation
Fdfs swapfs tmpfs
Mount metainformation areas as filesystems
mntfs cachefs lofs
fifofs specfs udfs namefs
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Logical-Operations [1 Certification Exam(s) ]
Lotus [66 Certification Exam(s) ]
LPI [24 Certification Exam(s) ]
LSI [3 Certification Exam(s) ]
Magento [3 Certification Exam(s) ]
Maintenance [2 Certification Exam(s) ]
McAfee [8 Certification Exam(s) ]
McData [3 Certification Exam(s) ]
Medical [69 Certification Exam(s) ]
Microsoft [374 Certification Exam(s) ]
Mile2 [3 Certification Exam(s) ]
Military [1 Certification Exam(s) ]
Misc [1 Certification Exam(s) ]
Motorola [7 Certification Exam(s) ]
mySQL [4 Certification Exam(s) ]
NBSTSA [1 Certification Exam(s) ]
NCEES [2 Certification Exam(s) ]
NCIDQ [1 Certification Exam(s) ]
NCLEX [2 Certification Exam(s) ]
Network-General [12 Certification Exam(s) ]
NetworkAppliance [39 Certification Exam(s) ]
NI [1 Certification Exam(s) ]
NIELIT [1 Certification Exam(s) ]
Nokia [6 Certification Exam(s) ]
Nortel [130 Certification Exam(s) ]
Novell [37 Certification Exam(s) ]
OMG [10 Certification Exam(s) ]
Oracle [279 Certification Exam(s) ]
P&C [2 Certification Exam(s) ]
Palo-Alto [4 Certification Exam(s) ]
PARCC [1 Certification Exam(s) ]
PayPal [1 Certification Exam(s) ]
Pegasystems [12 Certification Exam(s) ]
PEOPLECERT [4 Certification Exam(s) ]
PMI [15 Certification Exam(s) ]
Polycom [2 Certification Exam(s) ]
PostgreSQL-CE [1 Certification Exam(s) ]
Prince2 [6 Certification Exam(s) ]
PRMIA [1 Certification Exam(s) ]
PsychCorp [1 Certification Exam(s) ]
PTCB [2 Certification Exam(s) ]
QAI [1 Certification Exam(s) ]
QlikView [1 Certification Exam(s) ]
Quality-Assurance [7 Certification Exam(s) ]
RACC [1 Certification Exam(s) ]
Real-Estate [1 Certification Exam(s) ]
RedHat [8 Certification Exam(s) ]
RES [5 Certification Exam(s) ]
Riverbed [8 Certification Exam(s) ]
RSA [15 Certification Exam(s) ]
Sair [8 Certification Exam(s) ]
Salesforce [5 Certification Exam(s) ]
SANS [1 Certification Exam(s) ]
SAP [98 Certification Exam(s) ]
SASInstitute [15 Certification Exam(s) ]
SAT [1 Certification Exam(s) ]
SCO [10 Certification Exam(s) ]
SCP [6 Certification Exam(s) ]
SDI [3 Certification Exam(s) ]
See-Beyond [1 Certification Exam(s) ]
Siemens [1 Certification Exam(s) ]
Snia [7 Certification Exam(s) ]
SOA [15 Certification Exam(s) ]
Social-Work-Board [4 Certification Exam(s) ]
SpringSource [1 Certification Exam(s) ]
SUN [63 Certification Exam(s) ]
SUSE [1 Certification Exam(s) ]
Sybase [17 Certification Exam(s) ]
Symantec [134 Certification Exam(s) ]
Teacher-Certification [4 Certification Exam(s) ]
The-Open-Group [8 Certification Exam(s) ]
TIA [3 Certification Exam(s) ]
Tibco [18 Certification Exam(s) ]
Trainers [3 Certification Exam(s) ]
Trend [1 Certification Exam(s) ]
TruSecure [1 Certification Exam(s) ]
USMLE [1 Certification Exam(s) ]
VCE [6 Certification Exam(s) ]
Veeam [2 Certification Exam(s) ]
Veritas [33 Certification Exam(s) ]
Vmware [58 Certification Exam(s) ]
Wonderlic [2 Certification Exam(s) ]
Worldatwork [2 Certification Exam(s) ]
XML-Master [3 Certification Exam(s) ]
Zend [6 Certification Exam(s) ]