Data Centers

Backing up servers in multiple groups with Legato NetWorker

Follow this guide to create components in Legato Administrator to have multiple backup jobs run during one nightly backup.

In a previous article about Legato NetWorker, I showed you how to install the software and how to get a basic backup job up and running. At some point, however, you will need to fine-tune the backup. You can do this by either confining one server to a single tape or by dividing the backup so that the backup of a server resides on a single tape along with the backups of other servers.

In this article, I will walk you through the process of creating components in Legato Administrator that enable you to have multiple backup jobs running throughout your nightly backup. That way, you can place your mail server backup on one tape, your Oracle server backup on another tape, and your other servers’ backups onto yet another tape.

Create schedule for new pool/group
Before you create a new backup job, you must first create a schedule to govern what type of backup it will do on a particular day. To create a new backup schedule, go to NetWorker Administrator, right-click Schedules, and then select the Create option. When the Create Schedule screen appears, enter the name you want this schedule to be known by in the Name field. Then, you’ll have two options in the Period window—Month and Week. Selecting one of these sets the default as to when full and incremental backups will be performed. After creating a schedule, however, you have the option of overriding the default setting so that a full backup can be performed each day.

Although you have the option of creating an additional backup schedule for each backup configuration that you construct, I strongly suggest that you stick with one schedule for all your nightly backup jobs. Then, if you have to make changes (such as skipping a backup when you’re closed for a holiday), you only have to do it once.

Create new backup group
To create a backup group, go to NetWorker Administrator, select and right-click Groups, and then select Create. When the Create Group screen appears, enter the name that you want to give to this backup group. Although there doesn’t seem to be a naming limitation in Legato (such as having identical names for a label template, backup group, and pool), I usually try to make each name different to prevent confusion in the event that I have to do some debugging.

For backup group names, I like to use the initials of the company name followed by an underscore and the name of the server (or group of servers) that this backup group will be handling (i.e., TW_EXCH). By default, the start time will be 3:33 A.M. If you want your backup to start at 10:00 P.M., you will need to enter 22:00 for that to happen, as backups run on a 24-hour clock.

Before you schedule your backup groups to run, you should examine several nights’ worth of backup logs to see how long each backup job is taking. (It’s also a good idea to periodically examine the backup logs to make sure you aren’t having any problems.) The number of backup groups that can be running at the same time will be limited by the number of backup drives you have in your mini-library or the number of separate drives you have attached to the server running Legato NetWorker via a SCSI controller.

Although it’s possible for two backup jobs to be running at the same time, it’s a good idea to stagger the start times by 10 to 15 minutes. Then, if tapes have to be changed before the selected backup group can start, you won’t have to wait for the tape’s robot arm to finish with another task already in progress.

When you begin to schedule your backup groups to run, the default setting will show the Autostart field disabled. If this is a backup group that you intend to use only periodically, you can leave this field set to the default value. You will, however, need to change the field to Enabled if you want the backup group to automatically start each night at a specified time.

The next step is to select the backup schedule for this group. With Legato NetWorker, the schedule controls the days a particular backup group will be submitted for processing and backup. Therefore, the last field you need to work with is the Schedule field. Unless you have a particular need for running multiple schedules, I would strongly recommend that you use only one schedule, as that will save time in the event you need to skip a day of backup (i.e., national holiday).

Click the up or down arrow on the Schedule field until you see the name of the schedule that you previously created or already are using. Select the Schedule name, and then click OK to finish creating the new backup group.

Create label template for pool
This first step in creating the template is to set up the label, or text, that will be used when the tape for a particular group is initialized or prepared for use. There are three fields that you need to be concerned with when creating a label template:
  • Name. This is a name you create for the label template. You’ll use it to select the label template for a pool that runs as part of your nightly backup.
  • Fields. When initializing a tape, this is where you specify the items that make up the label name. One way of labeling the tape might be to use the group name followed by the calendar date on which that the backup is being run.
  • Range indication. This helps to keep someone from entering a number that doesn’t reflect an actual date in a month.

To create a label template, right-click Label Templates, and then click Create. When the Create Label Template screen appears, fill in the input fields. First, enter the Group name (i.e., Exch), press [Enter], and then enter the number range that is acceptable to use (i.e., 01-31). Once you have entered the information, click OK to finish.

Create pool for handling tape for backup group
In Legato, a pool is the entity that controls which servers are backed up onto the tapes that have been initialized with a particular label. To create a pool for the group of servers you want to backup, right-click on the Pools label in NetWorker Administrator, right-click on Pools again, and then click Create.

On the Create Pool screen, enter the name by which you want the pool to be known, the pool type (for this particular situation, you should enter Backup), and then select the appropriate label template from the drop-down list.

Label the tape
To label a tape, you’ll need to get to the Operations screen for your mini-library or single tape drive. If you’ve used ArcServe before, you’ll recognize this process as formatting the tape. For the purposes of this article, I will assume that you’re working with a mini-library. The processes for a single tape drive, however, will be similar to those for a mini-library.

If you are using multiple tape changers, this process is especially important; it ensures that you select the correct drive system, tape, and drive that you wish to format. First, double-click the Autochangers option in NetWorker Administrator. Then, select the mini-library that you want, and right-click it. Next, select Operations from the menu.

Now, an Autochanger Operations screen will appear. From this screen, click the Label button. Since you will be labeling one tape at a time, when the Autochanger Label screen appears, find the First and Last slot input fields and enter the number of the slot in the mini-library magazine for the tape that will be labeled first. Then, from the drop-down menu, select the pool name of the backup job for the tape you need to label. Next, click OK to start the labeling process. The process will take about a minute for each tape you want to label.

Depending on the amount of time you estimate the backup job will require to complete, you may want to consider formatting the tape in the drive in which it will run. You may also consider alternating the drives you use for labeling the tapes to equalize the time each drive in the mini-library is used so you don’t over use any one particular drive.

Leave an extra tape for each pool
If you use DLT tapes, you know they can be pretty expensive. However, you really should make the investment to have extra tapes for each pool. There are advantages to leaving an extra tape in the tape drive magazine each night. In the event that your backup job requires more tape capacity to backup the information than that for which you have left preformatted tape in the drive, this gives you a “spill-over” ability. With an extra tape already in the drive magazine, you’ll be able to complete the night’s backup without having to wait for an additional tape to be placed in the drive manually. Plus, the extra serves as a safeguard in the event that you forget to change or relabel tapes.

This is easy to do when you are only running a couple of pools that require only a tape or two apiece. When you starting having backup groups that each require multiple tapes, then you may have to decide how much of a safety net you want to have. You may still be able to have a spare tape to use when your backup exceeds its normal tape use, but you might not be able to cover a situation where the tapes don’t get changed or relabeled.

Check the daily tape usage
There are several tabs on the main NetWorker screen you should make use of in your daily backup system check. The Volumes tab shows you how much of each tape is actually used, as well as which drives, registry, and so forth have been backed up on the tape. Depending on how much of the information that you are backing up can be compressed, you should be able to get at least the uncompressed capacity of the tape drive in your mini-library.

For example, in backing up an Oracle server database, you will probably be able to get a 1.5 to 2.0 compression ratio of data between the server’s drives and the actual amount of space required on the tape being used for backup. This is due to the way Oracle sets up the drive tables to be used by the application running on the Oracle database server. An Exchange server on the other hand, will probably do little more than 1.0 to 1.2 compression ratios because of the database structure used by the information store in Exchange.

The Configure tab in NetWorker Administrator can give you details as to the success and/or failure of a particular backup job. In Administrator, double-click the Groups item, and you should see a listing of all the backup groups NetWorker is currently configured to use. To see the details of the last time a particular group was backed up, right-click the group’s name and then click Details. The screen that appears will show you a step-by-step report of what happened during a particular group backup.

Some have said that Legato NetWorker is a very complex backup solution. Even so, that’s not necessarily a bad thing. The added complexity is what gives it the flexibility and scalability to handle the type of multiserver backup situations that other backup solutions simply can’t handle. The best recommendation I can give is to start slowly with NetWorker and implement each feature on a step-by-step basis. In this Daily Drill Down, I have walked you through an example of how Legato NetWorker can change to meet your needs without the need to upgrade or purchase additional modules.

Ronald Nutter is a senior systems engineer in Lexington, KY. He's an MCSE, a Novell Master CNE, and a Compaq ASE. Ron has worked with networks ranging in size from single servers to multiserver/multi-OS setups, including NetWare, Windows NT, AS/400, 3090, and UNIX. He's also the help desk editor for Network World. If you’d like to contact Ron, send him an e-mail. (Because of the large volume of e-mail that he receives, it's impossible for him to respond to every message. However, he does read them all.)

The authors and editors have taken care in preparation of the content contained herein but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

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