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Tuesday, March 8, 2011

My Backup Strategy

Both my wife and I have suffered through a catastrophic hard drive failure in the past. Neither of us really enjoyed losing irreplaceable photos or countless hours trying to piece back together our digital lives. Since then, we've learned our lesson and took a few steps to reduce the likelihood of ever going through that again. So what exactly did we do? In short, we've started applying the 3-2-1 backup rule:

We recommend keeping 3 copies of any important file (a primary and two backups) We recommend having the files on 2 different media types (such as hard drive and optical media), to protect against different types of hazards. 1 copy should be stored offsite (or at least offline).

The Hardware

Recently I bought 2 1TB hard drives. I opted for the Western Digital Caviar Green. They offered a decent amount of size and performance for the price. An added benefit of these drives is that they're fairly quiet and turn themselves off when they aren't in use. For drives that are only in use sporadically throughout the day these were perfect.

To hold these drives, I first considered using a SATA drive dock. However, being a Mac user I prefer the things on my desk to be well designed and look great. I had a really hard time finding a dock that met my standards. Design concerns aside, I've got a few cats that like to walk all over my desk. I'm not sure that having exposed electronics would be such a good idea. Moreover, I also needed a safe place to store the drive that wasn't in use. Hard cases do exist, but NCIX, the place I ordered my backup stuff from didn't sell any -- yet another nail in the SATA dock coffin.

Instead, I opted to get a few enclosures by Macally -- the G-S350SUAB to be precise. These enclosures look just like tiny Mac Pro towers. Being made of aluminum they don't require any fans to keep quiet, and since the tolerances are fairly tight they don't rattle when the drive spins up.

The Software

I sliced up each of the drives into 3 partitions: a 120GB, 240GB, and 640GB.

The 120GB partition is the same size as the internal drive in my MacBook Pro and is used as a clone of the internal drive -- cloned with SuperDuper! an awesome tool for cloning drives for the Mac. Having a clone means that I don't need to go to the trouble of replacing the internal drive, installing the OS, and restoring data immediately. All I need to do is reboot off of the clone and I'm up and running with a fairly recent backup. However, just having a clone isn't enough. Typically cloning takes a long time to run and therefore is done less often. In my case it's done nightly but sometimes I'll go a few days without running it.

With the 240GB partition I use Time Machine. Every hour or so Time Machine will make an incremental backup of what's on my Mac. Having this partition be larger than the internal drive means that I can keep several revisions of files in case I need to restore old versions or deleted files. Incremental backup decreases the mean time between backups. I can't boot off of the Time Machine backup, but the number of files changed since the last clone will probably be small and can be restored to the clone if need be.

The last partition, large partition stores archived data -- photos, music, old projects, etc. Stuff that I don't need to work with regularly. The archived files on this partition are cloned from a Time Capsule I have running on the network (2 copies of everything, remember).

In order to get the offline side of the 3-2-1 backup I swap out the hard drives once a week. If the house were to burn down, or someone stole everything the most I'd be out is a week's worth of work. And since most of my work is stored in Dropbox anyway it's likely that I'd lose less than that.

Weaknesses and Pain Points

So far this strategy is working fairly well. It can be a pain to have to swap the drives but since I only have to do this once a week the pain is tolerable. I could have opted for an online storage system like Carbonite or Crashplan but decided that I wanted to do the whole thing myself without worrying about long restore operations, monthly fees, or feeling socially obligated to host someone else's backup. This does mean, however, that if there were an earthquake and the city was levelled I'd lose my data but I'm pretty sure that my data would be the last thing I'd be thinking of if that were to happen.

Time Machine automatically remembers some identifying information about the drive used as the backup drive. When I do my weekly swap I have to force Time Machine to do an initial backup. This prompts Time Machine to warn me that I might be backing up to another drive and performs a fairly long scan and backup on that first hit. It doesn't back up every file, it's still smart about just backing-up the files that have changed, so it's not as bad as it could be.


In the end I'm fairly happy with my backup plan. It's not perfect, but I feel safe knowing that my data is well protected and that the chance of me losing all of my and my families important data is low.