On Thu, Jul 5, 2012 at 12:35 PM, Stan Hoeppner <s...@hardwarefreak.com> wrote: > On 7/5/2012 2:44 AM, Adrian M wrote: > >> Hi Stan, >> I know how to add drives to the storage and how to grow the existing >> filesystem, but such big filesystems are somehow new to mainstream >> linux. Yes, I know some university out there already have pentabytes >> filesystems, but right now stable linux systems have trouble >> formatting ext4 partition over 16T. >> All this is telling me that is safer to have two or tree smaller >> filesystems than a big one. Dovecot has a nice feature for this >> "Directory hashing" http://wiki.dovecot.org/MailLocation/ > > At 16TB+ scale with maildir you should be using XFS on kernel 3.x, not > EXT4. Your performance will be significantly better, as in 30% or much > more. The typical XFS filesystem in the wild today is 50TB+ and there > are hundreds of XFS filesystems well over 100TB deployed around the world. > > NASA has XFS filesystems of 380TB and 535TB, and also has multiple 1PB+ > CXFS (cluster XFS) filesystems. 20TB is a tiny snack for XFS, 500TB is > lunch, 1PB is a big supper. A single XFS can scale to 16 Exabytes, or 1 > million terabytes, though the largest deployed so far that I'm aware of > is NASA's 535TB XFS. It'll scale to anything you'll ever throw at it, > and much more. > >> What I don't know is a nice way to migrate from a single directory no >> hashing to more than one and hashing. > > It's a good time to migrate to XFS. > > -- > Stan
Hi Stan, I already have xfs, and kernel 3.x. Switching from kernel 2.6.x to 3.x a couple months ago did indeed decrease the iops number.