One of the simplest rules of systems administration is that disks and systems fail. If you haven’t already lost a system or at least a disk drive, consider yourself extremely lucky. You also might consider the statistical possibility that your time is coming really soon. Maybe it’s just me, but I lost four laptop disk drives while trying to write this book! (Yes, I had them backed up.)
This chapter talks about developing an overall disaster recovery plan, of which your backup and recovery system will be just a part.
My father used to tell me, “There are two types of motorcycle owners. Those who have fallen, and those who will fall.” The same rule applies to system administrators. There are those who have lost a disk drive and those who will lose a disk drive. (I’m sure my dad was just trying to keep me from buying a motorcycle, but the logic still applies. That’s not bad for a guy who got his first computer last year, don’t you think?)
Whenever I speak about my favorite subject at conferences, I always ask questions like, “Who has ever lost a disk drive?” or “Who has lost an entire system?” Actually, this chapter was written while at a conference. When I asked those questions there, someone raised his hand and said, “My computer room just got struck by lightning.” That sure made for an interesting discussion! If you haven’t lost a system, look around you . . . one of your friends has.
Speaking of old adages, the one that says “It’ll never happen to me” applies here as well. Ask anyone who’s been mugged if they thought it would happen to them. Ask anyone who’s been in a car accident if they ever thought it would happen to them. Ask the guy whose computer room was struck by lightning if he thought it would ever happen to him. The answer is always “No.”
While the title of this book is Unix Backup & Recovery, the whole reason you are making these backups is so that you will be able to recover from some level of disaster. Whether it’s a user who has accidentally or maliciously damaged something or a tornado that has taken out your entire server room, the only way you are going to recover is by having a good, complete, disaster recovery plan that is based on a solid backup and recovery system.
Neither can exist completely without the other. If you have a great backup system but aren’t storing your media off-site, you’ll be sorry when that tornado hits. You may have the most well organized, well protected set of backup volumes,[1] but they won’t be of any help if your backup and recovery system hasn’t properly stored the data on those volumes. Getting good backups may be an early step in your disaster recovery plan, but the rest of that plan—organizing and protecting those backups against a disaster—should follow soon after. Although the task may seem daunting, it’s not impossible.
[1] This book will use the term volume instead of tape whenever appropriate. See Section 2.1.1 in Chapter 2 for an explanation.
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