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[_] Backups; best practice?

Oliver Humpage oliver at watershed.co.uk
Fri Dec 19 10:33:03 GMT 2008

On 19 Dec 2008, at 10:13, Oliver Humpage wrote:

> As I understand it, each time you run rdiff-backup, what it does is
> work out what's changed since the last backup, save those differences
> as diff files (and/or a metadata file, e.g. in the event a file's
> been created or deleted), then copy over the changed files to the
> "main" backup folder.

I meant to say, the brilliant advantage is that the main backup  
folder is always your most up-to-date backup, like a full snapshot,  
except for a single "rdiff-backup-data" folder in it.

Also, all diffs are automatically compressed to save space. For  
example, a 21GB home dir, mostly full of heavily used maildir format  
mailboxes, has a 5GB rdiff-backup-data folder which contains 3 diffs  
a day for the last 30 days.

Don't forget, though, that if you're backing up any databases you  
must do it with mysqldump, preferably locking tables. Just backing  
up /var/db/mysql isn't going to guarantee anything. You could run a  
mysqldump script just before doing an rdiff-backup which includes  
your dump folder, and it'll just diff the differences between the  
database files (I always back up each database to a separate file).

Oliver.