Chapter 9. Backup

Performing backups on your Linux system is important for various reasons. As with any system, you could experience a hardware problem. Similarly, the software on your system could become corrupted or someone could accidently delete it. Similarly, over time, you'll probably customize your system. If you have to reinstall it, you will loose all your customizations. Backups can save you lots of time in all these situations.

Many issues are related to backup. First, you must consider the frequency of system backups. You may decide to protect your data with some kind of storage technology (such as mirrored disks), but even that is not without risk. With mirrored disks, even if your system disk becomes corrupted, your data remains intact. Still, even mirroring doesn't help with deleted or corrupted files. Further, if you have to use your mirrored disk to restore your files, you will be unable to use your system while you restore it (unless you employ some high-availability program, such as ServiceGuard).

Similarly, if your system backup takes place to a tape device on a remote system, you'll have to consider the additional latency introduced by the network overhead.

For all these reasons, it is important to test your recovery plan after you have designed your backup technique. Testing your plan ensures that you can recover your systems and data within the window required by your operation.