At the Redgate SQL Privacy Summit recently, there was panel I hosted that I thought was really interesting. At one point someone asked a question and there was a bit of a discussion about the right to forget in the EU. One of the fascinating things wasn't about the rights, but about backups. One of our panelists noted that we often keep too many backups, most of which are really useless.
This portion of the discussion started by asking how many backups people keep. Many of those in the audience kept many backups, sometimes dozens. Many of them had some rotation scheme that determined how many files were kept over time. I know I've worked in places where we kept over a week or two worth of backup files, often along with a monthly or quarterly backup for a year and then multiple year end backups in perpetuity. I guess since we didn't really know how long those backups were valid as we just marked some tape as the end-of-year one and left it in a vault somewhere.
What was also interesting is the panelist asked if many people had restored a backup more than a month old. Almost no one had, but a few had restored a year old backup. I think that's common, and I find I've only restored one backup more than a month old. That one was actually for a legal case, and it was six or seven years old. I actually had to find someone at Microsoft that could provide us with an old version of an SP to restore the database.
I'm wondering today about the rest of you. Not if you have done it, but would you do it today? How far back would you go for a backup of an important database? Assume this isn't any requirement to find the data at a point in time, but for recovery purposes in a disaster.
For me, I'd expect that most of the systems I've managed really would have struggled to go back a week. After that point in time, so many transactions are missing that there are serious repercussions. This is why I've often ensured I had automated restores happening all the time, since I need to be sure that we can restore from yesterday or two days ago. If I went back more than a week, it would be because we had corrupt backups. While the business would probably survive, I'm not sure my job would. If I hadn't been able to produce a workable backup for the last week, I think most organizations would be justified in terminating me.
Whether they would or not is another debate.