Raphael Bittencourt S. Costa wrote:
And backup is a problem here, so an security filesystem is very important for not losing mail.
I have been using rsync (rsnapback) for many of my backups, but it struggles when you point it at hundreds of thousands of files in a directory. I have seen a number of solutions involving running multiple independent rsyncs for each maildir to keep the file numbers reasonable, but it's a bit of a fiddle
More recently I was reading webmail.us / rackspace's notes on their backup strategy and they have presentation on their use of S3 which is kind of cool. Reading between the lines they use something like an MD5 hash of all their files and then copy the files up to remote storage (S3) based on the file hash name. They then use some kind of index to record who has which files and which maildirs they belong in. Seems fairly cheap to make incremental backups and robust to maildirs tendency to move thousands of files from new/ to cur/...
There is an implementation of a similar algorithm via "brackup" - it might be interesting for your needs? I plan to do some more investigation into it for backing up our maildirs http://search.cpan.org/~bradfitz/Brackup/
Regards
Ed W