Hacking Together a Backup System

Jul 23, 2011, 5:10 PM

Tags: projects

Recently, my living room Mac mini's external drive, where it kept its iTunes library, met a horrible, clicking death. Naturally, I had devised a proper backup plan long before this happened - unfortunately, however, I had not yet implemented this plan. Crap.

So I decided to straighten out my backup system all around, ideally covering all of the machines in the apartment as well as my hosted Domino server. My ideal (at least for now) backup plan would fit within a couple attributes:

  • Cheap. I've been trying to spend less money overall lately, and picking up a new bill for hardware or services would counteract that somewhat. I wanted to come up with something that would work with the hardware I had on hand, plus one purchased replacement HD.
  • Automatic. I don't want to have to remember any manual backup process, since I most likely wouldn't.
  • Off-site backup isn't important. Sure, it would be nice to keep my data in the event of a physical catastrophe, but we're talking about TV shows and movies here, not anything vital.
  • Quick recovery or automatic failover aren't important. They'd be NICE, certainly, but I'm just looking for a basic "the data exists in at least one other place" setup. If a computer meltdown means that recovery will take a while or I'll have to rebuild the OS, that's fine.
  • Versioning isn't important. The occasions where I would want to restore intentionally-deleted files or modified documents are so few and far between that it's not worth going out of my way to achieve that.

My main laptop was far and away the easiest to set up. A while ago, my boss gave me an external USB drive which I've been using for Time Machine backups. Time Machine does pretty much everything I would want to, and even gets bonus points for ease of recovery and versioning. When I'm out of the office, it even kind of counts as off-site.

My Domino data was the next easiest, primarily since I work with it all the time. I set up a Parallels virtual machine to run a new Domino server, set up scheduled replication, and pointed my "create a replica of everything" agent at my production server. Voilà: up-to-the-hour backups without having to give it a second thought.

The hard drive I purchased to replace the failed one was a nice 2 TB one, giving me enough room to store my media library plus some Time Machine backups for the mini itself, the iMac in the bedroom, and the two other laptops floating around. It won't be enough space permanently, but it'll last me at least until I'm comfortable enough to buy another one. So that covers the other Macs themselves.

In addition to the media drive, the Mac mini also has a 750GB drive salvaged from my poor, video-card-exploded iMac. I cleaned off enough old crap from there that it will be able to serve as a mirror for the media files on its larger brother - again, at least for now. To implement that, I wrote a quick, two-line shell script:

rsync -aE --delete /Volumes/Tartaros/Movies /Volumes/Diaspar
rsync -aE --delete /Volumes/Tartaros/iTunes /Volumes/Diaspar

That basically mirrors the Movies and iTunes folders on Tartaros (the media drive) to equivalent folders on Diaspar (the iMac's old drive). The "-a" switch toggles "archive" mode, which enables a lot of useful behaviors for this case, "-E" enables support for HFS+ metadata like ACLs, forks, and extended attributes, while "--delete" removes any files in the target directory that no longer exist in the source. I added this to my crontab to run at 3 AM each day.

All in all, I think this setup should cover my basic needs pretty well. My next step, when I want to spend the money, will be to sign up for an online backup service like CrashPlan. There are some cheap options and they would hopefully be more reliable than my current scheme, which is still dependent on the fragile health of a handful of external USB drives.

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