Three is two, two is one, one is zero
You’ve probably heard the saying that “three is two, two is one, one is zero” in the context of survival strategies.
I use it in the context of data backups.
In my usage, if you have one copy of some data (a picture, a PDF, a document), you might as well have zero copies of that data: If it’s deleted or corrupted, you’re hosed.
If you have a backup, you have two copies of your data. But under the same principle, one backup means zero backups, if that backup goes south on you.
You want multiple copies of your data, and that means multiple backups. Where those backups are also makes a difference. There’s no point in having multiple backups if they’re all in the house that catches fire or is flooded, so having a remote backup is crucial.
I use a three level backup strategy that gives me some piece of mind. This might be overkill for some, but sometimes I feel it’s still not enough.
Most of my working data resides on my Apple 5K iMac. I have the following backups:
- Local, to an Apple AirPort Time Capsule. This creates hourly backups to a drive inside the house. It’s my first line of defense against stupidity. If I accidentally delete a file, I have a recent copy I can get to quickly and with a minimum of fuss.
- Local, to a Drobo 5D, using Cronosync to copy data daily. It’s meant as a redundant local backup in case something goes wrong with my Time Capsule.
- Offsite, to Backblaze. A remote copy is a requirement in case of physical damage to your local backups (such as fire, flood or theft).
- Off-site, to Dropbox for most (though not all) of my data. I limit this to “active” files due to storage limits with Dropbox (1 TB for $99/year for individuals). It’s technically not a backup because these are working files, but Dropbox keeps copies of any changed or deleted files for 30 days.
This gives me up to five copies of my data: the original, and four backups: two local, two remote.
(I actually have more than that, because I currently copy some of my Drobo 5D backups to a second Drobo, and some data gets synced to my computer at work, which itself has multiple backups,… but that’s too complicated to get into in any detail.)
The other piece of course is to test your backups.
For me this means occasionally trying to recover files from Time Machine on my Mac, opening files on my Drobo, and restoring files from Backblaze. There’s no point in having all these backups if I can’t actually get my data back.
And they’ve saved my bacon before.
I can’t preach this any more loudly:
* Backup Your Data
* Test Your Backups
Originally published at Jasonian: Of, or relating to, Jason..