Am 01.12.2014 um 17:24 schrieb absolutely_free@libero.it:
I'm going to set up a new storage for our email users (about 10k). It's a network attached storage (Coraid). In your opinion, what is the best file system for mail server (pop3/imap/webmail) purpose?
It depends on how conservative you are. Btrfs won't cut it, because too slow and still too much experimental.
ZFS on Linux is being maintained outside the kernel and eats up memory like a horde of cockroaches. So this is also for most no viable choice.
This brings down either ext4 or XFS. Both file systems have a decade old code base and are quite mature.
If you need the ability to shrink a file system, it's ext4. If you are on the conservative side, it's also quite ext4.
If you are feeling a little bit more adventurous, it's XFS. Note that XFS had some serious bottle necks in writing to its journal which have been solved in kernel 3.3.
XFS is kinda a somewhat difficult topic; some people love it and have no problems with it at all, while other people say they've seen serious problems with it.
There's been for example a talk by Peer Heinlein on Linux Tag 2012, where he gave us his insights about migrating his mail user base (> 100.000 accounts on roughly 12 TB storage) away from Maildir to mdbox.
He told there that he had seen at least three cases of XFS failure and therefore he considers it unreliable; he switched from ext3 to ext4.