Unix Backup and Recovery

Deciding What to Back Up

Experience shows that one of the most common causes of data loss is that the lost data was never configured to be backed up. The decision of what to back up is an important one.

Plan for the Worst

When trying to decide what files to include in your backups, take the most pessimistic technical person in your company out to lunch. In fact, get a few of them together. Ask them to come up with scenarios that you should protect against. Use these scenarios in deciding what should be included, and they will help you plan the “how” section as well. Ask your guests, “What are the absolute worst scenarios that could cause data loss?” Here are some possible answers:

• An entire system catches fire and melts to the ground, leaving an unrecognizable mass of molten metal and blackened, smoking plastic.

• Since this machine was so important, you, of course, had it replicated to another node right next to it. Of course, that machine catches fire right along with this one.

• You have a centralized server that controls all backups and keeps a record of backup volume locations and what files are on what volumes, and so on. The server that blew up sits right next to this “backup server,” and the intense heat took this system with it.

• The disastrous chain reaction continues, taking out your DHCP server, NIS master server, NFS home directory server, NFS application server, and the database server where you house the inventory of all your backup volumes with their respective locations. ...