Machine backups using tarsnap

I’ve got a dedicated server that I’ve been backing up for the past few years. My crude backup system involved taring everything to local disk and then rsyncing it to a remote server. It worked well at first, but as the amount of data grew it was taking half a day to run. Add to that the amount of disk space being used by the local copy and I had to find a better solution.

I started off by looking at replacements for rsyncing to my remote server. rdiff-backup seemed an obvious choice, but some friends had previously had problems with it, so I decided to give it a miss. There were various other similar tools that involved copying my data to another server (of mine), possibly with incremental features, but I decided to expand my search criteria and came across online backup services.

These services involve paying someone else to store your data remotely. In principal there didn’t seem to be much point; I had somewhere else to put my data, so why pay for it? One solution that seemed quite nice was brackup – a set of perl scripts that backed up to Amazon S3. Still not quite what I wanted though.

Then, I remembered a project Colin Percival was working on – tarsnap. It’d be a while since I last checked up on progress so I was quite pleased to see that he’d just launched the public beta. I signed up and handed over some money. What made me decide on this solution over others? Well,

1. It works pretty much like tar, except the archives are remotely stored. So that made it simple to use and fit it to my way of working.

2. It has all the benefits of snapshots with all the benefits of incremental backups. By this I mean that you can access each archive as if it was a full copy, but behind the scenes it only transmits and stores the differences (and charges you accordingly). You can delete any archive in the set without worrying about things like needing all the incrementals to the last full backup, and it sorts it all out for you.

3. Colin is a FreeBSD guy, so that pretty much guarantees it’s going to work well on FreeBSD and be supported in the future.

4. After doing the sums I realised the charges are pretty insignificant compared with the cost of running my own dedicated server.

5. There’s a whole load of stuff about security. It doesn’t particularly interest me though, but it’s nice to know my data is safe (nobody can read it – Colin included – without my key).

So I’ve been using tarsnap now for a few months and on the whole I’ve been very happy. There was a minor issue with the large number of files (Maildir email storage can get insane :-) ) I had to backup, but once I discovered the --lowmem flag all was fine. And Colin’s support has been great – he’s always been quick to answer if I’ve had a question or problem.

If you’re looking for an online backup service that’s geared towards Unix systems I highly recommend giving tarsnap a try.

(How about reading my post on Automating Tarsnap Backups?)


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