Remote storage disaster recovery for Windows 2000 networks
If data is saved on remote storage tapes, you're safe, right? Well, maybe not. Brien Posey reminds you can things can go wrong when tapes are constantly overwritten, and he explains how to avoid and recover from storage disasters.
When it comes to working with remote storage, many administrators have a false sense of security. After all, we've always been taught that if it's on tape, it must be safe. Remember that a remote storage tape functions differently from a backup tape. Remote storage tapes are constantly being overwritten and are usually constantly available online. Backup tapes, on the other hand, are written to and then removed and stored in a safe place. Because of the nature of remote storage, a lot can go wrong. This is even more true when you consider that the Windows 2000 implementation of remote storage is new, and administrators are more likely to make a mistake then they would be if they were using familiar technology. In this article, I'll discuss some of the things that can go wrong with remote storage media and some techniques you can use to recover from such disasters.
Backing up Windows 2000I've seen many instances in which network administrators backed up the data from a server, but not the operating system. If you're using remote storage, this isn't a practice that you want to engage in. Sure, the biggest part of backing up remote storage deals with the tapes; but a copy of the remote storage database actually resides at %SYSTEMROOT%\SYSTEM32\REMOTESTORAGE. A duplicate copy of this database also resides on the remote storage tape. However, if you were to lose the main copy, the process of retrieving the copy from tape is extremely long and complicated. If you get desperate and have to pull the copy from tape, you can find instructions for doing so in the Microsoft Knowledge Base.
Single tape drive techniquesBacking up and restoring remote storage is easiest if you have two identical tape drives. However, you can still make a backup on systems containing a single tape drive. To do so, you'll have to use a tape drive attached to another machine to back up remote storage. In such a situation, you can back up remote storage files in the same manner you would back up any other files. (It's important to do this from time to time even if you have multiple tape drives, because you can't restore the remote storage database to another computer.) If you ever need to restore files from remote storage to another system because of low hard disk space, the restoration will work only if the files were backed up using this method.
Multiple tape drive techniquesIf you have two identical tape drives attached to the server, you can actually copy your remote storage tapes. Keep in mind that I recommend still performing your normal nightly backup, just as you would on a single tape drive system. However, making copies of the remote storage tapes is a good way to supplement your disaster recovery library. The great part about doing this is that if you have a really big disaster, you can restore your operating system (and the remote storage database that it contains) from tape. After that's done, you don't have to worry about restoring the remote storage tape. Instead, you can just insert the copy you made, click a few buttons, and you're back in business.
Working with remote storage media
|Multiple media masters
It's possible to have more than one media master. For example, you would have multiple media masters if you had too much data in remote storage to fit onto a single tape. A group of media masters is referred to as a master set.
Other tasksSo far, I've discussed procedures for backing up remote storage files under a variety of conditions. However, all the backups in the world won't do you any good unless the data you're backing up is good. I recommend that you occasionally verify the integrity of your remote storage system. Doing so involves checking out the place holders and cached files to make sure they are still linked to their corresponding files on the tape. When you set up Remote Storage, it automatically creates a validation schedule. Normally, the default validation schedule is enough to keep things running smoothly. However, you can use the Remote Storage MMC snap-in to check out this schedule. If need be, set the schedule to run more frequently. If you're implementing Remote Storage on multiple volumes, you should also check to make sure that the consistency check is being run against all necessary volumes.