Automatically backing up uploaded files? One of the news sites I'm developing is heavily reliant on its image database, which has been migrated from the old site and is ~15-20gb at this point.

It's dawned on me that it would be really bad if there was some sort of server malfunction and all of the images in that directory were lost -- they're generally created on-the-fly by one person every week from much higher-resolution versions that have been pushed so far back into a totally-disorganized archive that it would take ages to resize and upload them all again (Which isn't even going into the awful process that would be re-adding them to the site's ~15,000 article nodes). 

To this end, I'm looking for a way of backing up the uploaded images folder in sites/default/files. One thought I've had is to use Subversion's WebDAV Autoversioning capability, though I'm not overly sure how I'd get the Drupal 7 filefields to use this.

I could also just write a script to rsync files between two servers once a night -- the newspaper's office has a few servers for that sort of thing.

Any thoughts what a good backup solution would be for this particular situation?

Thanks!
I have not been in the situation before, if I were in your shoes I would take a look at the CDN module.

In File Conveyor mode (ie, a push model), it will automagically copy files up to your CDN of choice.  A side effect of this is the fact that the files will now live in two places.  You can go with one of the commercial CDNs, or you can set up your own with another server.