It's been almost exactly a week since the last post – an unusually long time for me. Kimberly and I were teaching the first week of the inaugural Microsoft Certifed Masters SQL course last week in Redmond (a little intense at 8 hours of *teaching* per 10-hour day – so no energy for blogging afterwards). Now we're in Vienna, where we're on-site with one of our favorite customers, then we head to Barcelona next week for TechEd EMEA, back to Vegas for SQL Connections the week after, and finally back to Seattle for PASS the following week. Phew! Look for a photo-stuffed Where In The World Are Paul and Kimberly post from Vienna next week.
I'll try to post some interesting stuff that comes up while we're at the conferences – always a good crop of questions.
In this quick post I want to touch on something that's becoming more important to explain as more and more people start managing systems who haven't got a lot of DBA experience (what I like to call involuntary DBAs). How do you plan a backup strategy? As you'll see if you look at my Backup/Restore category, I've got lots of info about specific types of backups but nothing on putting a plan together in the first place.
It's very simple to decide on using the SIMPLE recovery model and regular database backups – the backup schedule is easy. But, what happens when you come to recovering from a disaster? Which backups to you need to restore and how long does it take you? If you take weekly full backups, say, then you stand the chance of losing a lot of data if the disaster occurs just before your next full backup. So, if you switch to the FULL recovery model and add log backups, you can recover right up to the point of the crash.
But again, what backups do you have to restore and how long does it take you? Are you able to restore within the maximum allowable downtime for your business? If you have a 300-GB database, and the downtime allowance is 15 minutes (as with one DBA I've known), the answer is no. Do you need to move to a partitioned schema that makes use of multiple filegroups so that you can use partial database availability to bring your application online faster with only the critical filegroups?
The key point when planning a backup strategy is not to think about what backups you want to take – think about what restores you have to be able to perform, then work backwards from that.