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Backing Up the NetWare File System

Articles and Tips:

Mickey Applebaum

01 Sep 1998


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An intraNetWare or NetWare 4 server contains two components that you must back up: Novell Directory Services (NDS) and the NetWare file system. Because these components perform different functions, each component has a unique set of backup requirements, which you must follow to ensure that you can fully restore the component in the event of a server failure.

The last issue ofNetWare Connectionfeatured an article about backing up NDS. (See "Technically Speaking: Backing Up NDS,"NetWare Connection, Aug. 1998, pp. 43-45. You can download the article from http://www.nwconnection.com/aug.98/techsp88.) The following article focuses on backing up the file system.

UNDERSTANDING THE NETWARE FILE SYSTEM

Before you begin the backup, you should understand the type of information the NetWare file system contains and the file system information you need to back up. Obviously, the NetWare file system contains the files and directories stored on each volume. However, the NetWare file system also contains other critical information. Because many network administrators are not aware of this additional information, they mistakenly back up only the files and directories stored on the server, assuming that they have a complete backup of the NetWare file system.

For example, many network administrators think that file and directory trustee rights are part of NDS--not the NetWare file system. Actually, trustee rights are stored on each volume, so they must be backed up with the NetWare file system. The confusion may arise because you must restore User objects, which are part of NDS, before you restore trustee rights, which are part of the file system. (Because trustee rights are specific to users, you cannot restore these rights until User objects reside on the server.)

A similar misconception exists for file and directory ownership information: Although file and directory ownership information is specific to users, this information is part of the NetWare file system rather than NDS. In addition, the NetWare file system contains extended file attribute information, which includes file and directory flags such as Purge, Delete Inhibit, Copy Inhibit, Shareable, Last Accessed, and Last Modified.

The NetWare file system also contains information about size restrictions for both volumes and directories, as well as information about each volume's name spaces. For example, the NetWare file system contains long filename information for Windows NT, Windows 98, Windows 95, OS/2, Macintosh, and Network File System (NFS) name spaces.

To make a reliable backup, you must ensure that you have an error-free NetWare file system. If you suspect that the NetWare file system contains errors or that the volume tables are corrupted, you should run Novell's VREPAIR utility on each volume on the server. However, you should run the VREPAIR utility only if you believe a problem exists in the NetWare file system: Because the VREPAIR utility has such a powerful effect on volumes, you should not use this utility as a preventive maintenance tool. In other words, donotautomatically run the VREPAIR utility before you make each backup.

Novell recommends that you always use the latest version of the VREPAIR utility and the associated name space NetWare Loadable Modules (NLMs)--the V_MAC NLM, the V_LONG NLM, and the V_NFS NLM. You can find the latest version of the VREPAIR utility and the associated name space NLMs in Novell's intraNetWare Support Pack. (As we go to press, the latest version is intraNetWare Support Pack 5.0, which you can download from http://support.novell.com/misc/patlst.htm.)

INSTALLING BACKUP HARDWARE AND SOFTWARE

Before you begin the backup process, you should also ensure that you are using a tape drive and backup software that have been tested and certified by Novell to work with an intraNetWare or NetWare 4 server and Novell's Storage Management Services (SMS). SMS is an open architecture that defines how storage management products, such as Novell's SBACKUP utility and third-party backup software, access and store information for backup and restore purposes. You can find out more about SMS by reading the following articles:

LOADING TARGET SERVICE AGENTS AND BACKUP SOFTWARE

In addition to installing backup hardware and software, you need to load the appropriate backup target service agent (TSA) at the server console. TSAs serve as an interface between the server and the backup software you are using, allowing this software to access NetWare services. Novell makes each NetWare service, such as the NetWare file system or NDS, available to SMS-compliant backup software via a corresponding TSA.

Novell's TSA410 NLM allows you to back up the NetWare file system. If you do not load this NLM, you can back up only the files and directories stored in the NetWare file system and the DOS name space directory structure. (Novell recommends that you use the latest version of the TSA410 NLM, which is included in intraNetWare Support Pack 5.0. You can download intraNetWare Support Pack 5.0 from http://support.novell.com/misc/patlst.htm.)

To load the TSA410 NLM, enter the following command at the server console:

LOAD TSA410

You enter a similar command to load the backup software you installed. For example, if you were using the SBACKUP utility, you would enter the following command at the server console:

LOAD SBACKUP

PERFORMING THE BACKUP PROCESS

You are now ready to perform the backup process. Because each backup product provides a unique interface to identify backup tasks, this section includes general instructions that may not apply exactly to the backup software you use. You should be familiar with the particular backup software you have installed before you perform the backup process.

To perform the backup process, you complete three basic steps:

  • Specify the information you want to back up.

  • Create a backup job.

  • Schedule the backup job.

The main screen for your backup software lists the type of backup and restore tasks you can perform. From this main screen, you select the option that allows you to perform the backup process.

The backup software should then display another screen, listing available backup sources. This screen identifies the servers on your company's network. You can highlight the server you want to back up, or if you are using Windows-based backup software such as Computer Associates' ARCserve or Seagate Software's Backup Exec, you can double-click the server's icon. You can also select individual files or volumes if you do not want to back up the entire server.

In most cases, you would select a server as the backup source. Depending on the backup software you have installed, you may be prompted to enter a username and password that this backup software can use to log in to the server and access the NetWare file system. You should enter a username that has ADMIN rights to the NDS tree or SUPERVISOR rights to the server you are backing up.

As you know, NDS rights and file system rights are not the same thing: You can have SUPERVISOR rights to the NetWare file system, without having ADMIN rights to the NDS tree. This distinction allows you to control the backup process.

For example, suppose that your company's network contained multiple servers and you wanted to back up NDS only from the server that contains the master replica of the NDS tree. To prevent you or another network administrator from inadvertently backing up NDS from other servers, you could create a User object that had SUPERVISOR rights to the NetWare file system on each server. You could also make sure this User object had no rights to the NDS tree. Then you would log in as this User object to back up the NetWare file system on each server.

After you select a backup source, you may be prompted to specify the type of backup job you want to create. (See "Types of Backup Jobs.") You create a backup job by defining the backup tasks you want to perform. Your backup software should include options that allow you to specify whether you want to back up file and directory trustee rights, file and directory ownership information, volume and directory size restrictions, name space information, and so on. To make a reliable backup, you must select every available option. If you skip an option and you have to restore the NetWare file system from the backup you created, critical file system information may not be properly restored. As a result, users may not be able to access their files or their own home directories.

At this point, you can customize the backup job by defining optional backup tasks. For example, you can apply filters that prompt the backup software to exclude certain things, such as .TMP files, from the backup. You can also configure the backup software to use one of the following verification methods:

  • Full Verification. If you select this option, the backup software compares each file written to the backup tape against the original file stored on the server. This option is the best one, ensuring that every file is properly backed up.

  • Partial Verification. If you select this option, the backup software compares random files written to the backup tape against the original files stored on the server. If these files match, the backup software assumes that all of the files written to the backup tape are backed up properly.

  • Cyclic Redundancy Check (CRC). If you select this option, the backup software compares the parity information on the backup tape against the parity information on the server. If this information matches, the backup software assumes that all of the files written to the backup tape are properly backed up. This option provides the simplest, but least reliable, type of verification.

Although verifying the backup is optional, you should use this option to ensure that you have made a complete backup. Otherwise, you won't know if all of the file system information is included in the backup until you try to restore the NetWare file system from this backup in the event of a server failure.

After you have created a backup job, you select the backup target, which is the tape drive you are using. You then have the option of submitting the backup job immediately or scheduling the backup job to be performed later. If you select the scheduling option, you must specify the date and time at which you want the backup process to occur. You can also configure the backup software to automatically perform this process on a regular basis, such as every evening.

PERFORMING THE RESTORE PROCESS

Before you restore the NetWare file system, you must complete certain steps to recreate this file system in its exact state before the server failed. First, you repair or replace whatever made the server fail, and you reinstall intraNetWare or NetWare 4. You then restore NDS, ensuring that each User object is intact. (See "Technically Speaking: Backing Up NDS,"NetWare Connection.)

Next, you must install the backup hardware and software you are using and load both the TSA410 NLM and the backup software at the server console. Once you can access the backup hardware and software, you can restore the NetWare file system.

To perform the restore process, you complete three basic steps:

  • Specify the information you want to restore.

  • Create a restore job.

  • Schedule the restore job.

From the main screen of your backup software, you select the option that allows you to perform the restore process. At this point, you insert into the tape drive the backup tape that contains the latest complete backup you made, and you select the option to build a catalog of the information, ordataset, that can be restored from this backup tape. The backup software then scans the backup tape and builds the catalog.

After the catalog is completed, you create a restore job by selecting a dataset based on the date and time or on the name, depending on your backup software. You should select the latest complete backup dataset to restore the NetWare file system. If you performed an incremental or differential backup after the complete backup, you skip these datasets for now. You must first restore the NetWare file system from the latest complete backup dataset. (To learn the difference between full, incremental, and differential backups, see "Types of Backup Jobs.")

You are then prompted to specify a restore target by selecting the same server or volume from which you backed up the NetWare file system. Next, you select the file system information you want to restore. The backup software you are using should include options for restoring only files and directories with particular attributes or flags; file and directory trustee rights; file and directory ownership information; volume and directory size restrictions; name space information; and so on. To completely restore the NetWare file system, however, you select the option that allows you to restore all of the file system information.

You can then customize the restore job by defining optional restore tasks, which are similar to the optional backup tasks you can define when creating a backup job. For example, you can select files or directories to exclude from the restore process, and you can set verification rules. Verifying that you have restored all of the file system information is optional but highly recommended.

At this point, the backup software should prompt you to specify an action that should be taken when a file or directory to be restored already exists on the server. Depending on the backup software you are using, you should see options similar to the following:

  • Overwrite All Files. If you select this option, the backup software overwrites any file that already exists on the server with the same file stored on the backup tape. You should select this option only if you are sure that you need the exact files stored on the backup tape.

  • Overwrite Only Older Files. If you select this option, the backup software overwrites files that already exist on the server only if the same files stored on the backup tape have a newer date and time. In most cases, you should select this option, which ensures that the latest version of each file is restored.

  • Ask Prior to Overwriting Files. If you select this option, the backup software stops whenever it encounters a file that already exists on the server. You must then prompt the backup software to overwrite the file or to skip the file without restoring the backup file. If you are restoring a large number of files, you should not select this option because it requires extra time and intervention.

  • Overwrite None. If you select this option, the backup software does not overwrite any file that already exists on the server. You should select this option if you want to restore only files that do not already exist on the server.

After you select one of these options, you can submit the restore job immediately, or you can schedule the restore job to be performed later. In most cases, you should submit the restore job immediately so you can monitor its progress and detect any errors that may occur.

If you created an incremental or a differential backup in addition to a full backup, you should restore these datasets in the same way that you restored the complete backup dataset. Users should then be able to access the server, along with all of the file system information you just restored.

CONCLUSION

Although this article has covered the backup and restore processes in detail, you should be aware of some additional points before you begin these processes:

  • Most backup software cannot back up open files. As a result, you should ensure that users exit their applications and log out of the network before the backup process starts. Although some backup software allows you to force users' connections off of the network, doing so may cause file corruption.To avoid these problems, you can use backup software that supports open files, including Open File Manager from St. Bernard Software Inc. and ARCserve with Backup Agent for Open Files from Computer Associates Inc. However, you should not rely exclusively on this type of backup software until you test it.

  • Client-server database applications running on the server--including Oracle, Sybase, and Btrieve, as well as GroupWise and other applications that use a database--can also open files. To ensure that these files are included in the backups you make, you should follow the vendors' recommendations for backing up open database files. In addition, you should schedule a regular backup when the database application is shut down, providing the backup software with full access to database files.Many database applications include a feature that allows you to save open database files as a single archive file, which you can then back up. You can also use a separate utility designed for backing up open database files. If you wanted to back up open GroupWise database files, for example, you could use Novell's GWBACKUP and DBCOPY utilities. (See "Practical Networking: Backing Up Open GroupWise Database Files,"NetWare Connection, July 1998, pp. 38-44. You can download this article from http://www.nwconnection.com/jul.98/pracnt78.)

  • To be on the safe side, you should set up a server in a separate NDS tree, and you should use this server to periodically test the backup hardware and software you are using, as well as the backup tapes you have made. In this way, you can determine whether the backup hardware and software is functioning properly and whether the backup tapes contain reliable backups.You should also use this server to periodically test the restore process using one of the backup tapes. To ensure that this tape contains a complete backup, you should compare the restored file system and NDS information to the file system and NDS information you backed up.By following the steps outlined in this article and in the previous article in the series, you should be able to properly back up and restore an entire intraNetWare or NetWare 4 server. You can then recover from a server failure or a disaster without losing critical server information.If you want more information about backing up the NetWare file system, read the following articles:

  • "Backup Solutions: A Practical Example,"Novell Application Notes, Jan. 1998. You can download this article from http://developer.novell.com/research/appnotes/1998/january/anframe.htm.

  • "NDS Technical Overview: Novell Layered Services,"Novell Developer Notes, Aug. 1997, p. 46. (The "Directory TSA" section covers backup and restore issues.) You can download this article from http://developer.novell.com/research/devnotes/1997/august/a9frame.htm.

Mickey Applebaum has worked with NetWare for more than 14 years. Mickey provides technical support on the Internet for The Forums (http://theforums.com).

NetWare Connection,September 1998, pp. 38-42

Types of Backup Jobs

When you create a backup job, you may be prompted to specify the type of backup job you want to create. Although the options vary depending on the backup software you are using, most backup software offer the following options:

  • Complete Backup. If you select this option, the backup software backs up all files in all directories stored on the server or volume you specify or in the directory you specify, regardless of when the last backup was made and whether the files have already been backed up. NetWare then changes the Archive file attribute to indicate that the files have been backed up. To ensure that the Archive file attribute is being changed, you should check this attribute after the backup is completed.

  • Incremental Backup. If you select this option, the backup software backs up only files that have been created or modified since the last backup was made. When you create or modify a file, NetWare automatically sets the Archive file attribute to Not Backed Up. If you make an incremental or a differential backup, the backup software determines which files need to be backed up by checking the Archive file attribute and backing up all files with the Not Backed Up setting. After the backup software backs up these files, NetWare changes the Archive file attribute to indicate that the files have been backed up.

  • Differential Backup. If you select this option, the backup software backs up only files that have been created or modified since the last backup was made--just as with an incremental backup. The difference between an incremental backup and a differential backup is NetWare does not change the Archive file attribute after the differential backup is completed. Instead, the files maintain their Archive file attribute setting of Not Backed Up. These files continue to be backed up during each subsequent differential backup, until the next complete backup occurs.

When the next complete backup occurs, NetWare changes the Archive file attribute to indicate that the files have been backed up. As a result, these files are no longer included in each subsequent differential backup.

Differential backups offer a significant benefit when you are performing the restore process: Because each differential backup includes all of the files that have been modified since the last complete backup was made, you need to restore the server only from the last complete backup and the last differential backup.

Differential backups also offer a significant drawback: Because each differential backup includes all of the files that have been modified since the last complete backup was made, differential backups can take a long time to make. The longer the time since you made the last complete backup, the more files you have to back up as part of each differential backup.

If possible, you should make a complete backup every day, and you should configure this backup to overwrite the backup tape you are using. In this way, you can ensure that you always have the most recent files on hand, which you can then restore in the event of a server failure. For example, if you made a complete backup every night and the server failed on Wednesday, you could use the backup tape from Tuesday to do a complete restore.

If you cannot make a complete backup every day, you should make an incremental or a differential backup. For example, you might want to make a complete backup on Friday night, backing up all of the files for the week. You could then make incremental backups Monday through Thursday.

When you make an incremental or a differential backup, you should use the backup tape that contains the last complete backup and append the incremental or the differential backup to that complete backup. In the event of a server failure, you could then simply restore the server by using the complete backup from Friday night and each of the incremental backups from Monday through Thursday, thus ensuring that you have performed a complete restore.

If your tape drive does not provide enough storage capacity to append an incremental backup to the last complete backup on a single backup tape, you should make a differential backup instead. For example, you could make a complete backup on Friday night and then make differential backups Monday through Thursday. You could then use one backup tape for the last complete backup and another backup tape for all of the differential backups.

NetWare Connection, September 1998, p. 40

* Originally published in Novell Connection Magazine

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The origin of this information may be internal or external to Novell. While Novell makes all reasonable efforts to verify this information, Novell does not make explicit or implied claims to its validity.

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