Over the years, I’ve had many a discussion on Backup applications as well as strategies for how often to backup. As a follow up to the series of posts I did regarding upgrading to current Microsoft technologies, I thought I would put forward my thoughts on Backup options as well.
I will not be discussing the options chosen by my friend, but will instead talk about my opinions and “musings”. I figured I would install and test different Backup applications and include my findings here as well. Of course, I have access to Data Protection Manager 2010 from Microsoft, but how do I get my hands on some of the other products out there for testing purposes? A month ago, I did a joint event with Commvault and the folks there told me they would get me an evaluation copy for me to play with. As of today, I still haven’t received that and I can’t find a trial version to download off their website, so I’ll have to nix them from the list. In searching Symantec’s website, I found a 60 day trail version of Backup Exec 2010 R2 so I took the 30 – 40 minutes to download the 3 GB ISO image.
Before I actually test these two products (or any others), I thought I would first focus on strategies for backup first. What do I mean by this? I’m talking about how often to backup and what backup type should I use (Full, Differential, etc.). In the old days, before I joined Microsoft, I actually did work with small businesses and had to help customers come up with a strategy that worked for them. For the companies with minimal amounts of data (less than 100 GB), it was easy to just do Full Backups every night provided the Tape Backup hardware could support that. Nowadays, with backup to disk options, backups are much quicker and provide more flexibility to companies.
Let’s take a look at a fake company that has about 1 TB of data (combination of 750 GB of files, 200 GB of Exchange databases and 50 GB of SQL databases). Assuming I get pretty darn good backup performance of 100 GB / hour, I can complete a full backup (in serial) in about 10 hours.. If I can backup the three different types of data in parallel, I could complete a full backup in 7 1/2 hours. Now, do I really need to do a full backup every night or can I get by with only one or two full backups a week supplemented by incremental or differential backups? I’m willing to bet in most companies, only about 30% – 40% of the data actually changes on a daily basis (not counting Exchange and SQL). In my example, 40% of changes to the data files would equal 300 GB. If I perform a differential backup of the data files combined with Full Backups of Exchange and SQL, my nightly backup window would only be 3 hours and take up less space in my Backup environment. The challenge with this strategy, is that a restore would take more work – restoring the Full and the a bunch of incrementals. The other option would be to do differential backups every night. I’m willing to be that the same set of data files are updated on a regular basis so even with differential backups, the total size of changed files (since the last full backup) will still only be about 50% which in my case would be 375 GB. With this option, the backup window would be under 4 hours for most nights and then 10 hours for the nights I would perform a full backup.
Perhaps the backup schedule would look like this:
Saturday – Thursday Backup Start Time: 10 PM Backup Type: Differential Friday Backup Start Time: 10 PM Backup Type: Full
At the end of every month, I might consider doing a full backup regardless of what day of the week it is. Then, I would take a copy of this and store it off site.
I admit, the above viewpoint is one based on “traditional” backup strategies. Today, there are options that allow companies to take snapshots of their data and therefore backups can take only minutes to complete and take up less space than normal. Since I don’t manage a production environment, I have never fully tested these options before (nothing beyond installing and performing a simple test). Over the course of the next week or so, I plan on installing and testing more thoroughly different backup applications and then reporting back on my experience.
Other than DPM 2010 and Backup Exec 2010 R2, anyone want to suggest some other common applications for me to look at? I can’t guarantee I’ll be able to get my hands on these applications, but I will try to test a few more than just the two I mentioned.