On Tue, Dec 15, 2009 at 5:28 PM, Bill Sprouse <bill.spro...@sun.com> wrote: > Hi Everyone, > > I hope this is the right forum for this question. A customer is using a > Thumper as an NFS file server to provide the mail store for multiple email > servers (Dovecot). They find that when a zpool is freshly created and > populated with mail boxes, even to the extent of 80-90% capacity, > performance is ok for the users, backups and scrubs take a few hours (4TB of > data). There are around 100 file systems. After running for a while (couple > of months) the zpool seems to get "fragmented", backups take 72 hours and a > scrub takes about 180 hours. They are running mirrors with about 5TB usable > per pool (500GB disks). Being a mail store, the writes and reads are small > and random. Record size has been set to 8k (improved performance > dramatically). The backup application is Amanda. Once backups become too > tedious, the remedy is to replicate the pool and start over. Things get > fast again for a while. > > Is this expected behavior given the application (email - small, random > writes/reads)? Are there recommendations for system/ZFS/NFS configurations > to improve this sort of thing? Are there best practices for structuring > backups to avoid a directory walk? > > Thanks, > bill > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >
Anyone reason in particular they chose to use Dovecot with the old Mbox format? Mbox has been proven many times over to be painfully slow when the files get larger, and in this day and age, I can't imagine anyone having smaller than a 50MB mailbox. We have about 30,000 e-mail users on various systems, and it seems the average size these days is approaching close to a GB. Though Dovecot has done a lot to improve the performance of Mbox mailboxes, Maildir might be more rounded for your system. I wonder if the "soon to be released" block/parity rewrite tool will "freshen" up a pool thats heavily fragmented, without having to redo the pools. -- Brent Jones br...@servuhome.net _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
