Backing up a VPS with duplicity?

I’ve got a total of 3 VPS’s from different providers now and I’ve been trying to decide the best way to back them all up. Plus I’ve got about 7GB of documents, photos and videos on my home PC and if everything could be backed up to the same place then even better.

For the past month I’ve been using Amazon’s S3 along with Duplicity.

There are a few really good points to using this method –

• the later versions of duplicity are built to work with S3, it’s one of the many options
• duplicity only sends files that have changed since the last backup reducing the bandwidth you use
• S3 is pretty cheap and you would hope, being Amazon, that your data is pretty secure
• although not mountable as a filesystem yet you can access S3 through a plugin in firefox
• it is possible to encrypt your data on S3

but there are definitely some downsides too –

• backups are stored in a propriety format

meaning that if you want to get at your data through a web browser while you’re on the road then you’re out of look. Also, I’m assuming, if one of the backup files got corrupt then you could be in trouble restoring your data

• backups from the 3 vps servers are accessible from the other servers

You use a key to access your Amazon account. This is stored in a script (if you want your backups automated) so if one of your machines did get (root) compromised then the backups from that machine and the other machines would be accessible by the hacker. It would be possible to limit this I guess by creating different Amazon accounts for your different servers but this would be a real pain to manage.

• because you are charged by the GB stored and for bandwidth it would be possible to run up a huge balance

If for some reason duplicity got stuck in a loop, or your machine got compromised, it would be possible to get rather a large bill from Amazon. It is possible to check how much bandwidth you are using on a daily basis but I’m not sure anyone would actually do this. I’ve not seen anywhere you can put a limit on your Amazon account to prevent this.

• you can’t mount your Amazon S3 space as a linux filesystem

I’m pretty sure someone will make this possible soon, and I’ve seen a couple of projects with this aim, but it’s definitely a shame you can’t do it now.

Backups should be reliable, secure and simple and at the minute this solution doesn’t feel that way.

I’m backing my VPS’s up this way but am still using iDrive for my PC data