Re: [zfs-discuss] zpool fragmentation issues? (dovecot)
In my previous post I was refering more to mdbox (Multi-dbox) rather than dbox, however I beleive the meta data is store with the mail msg in version 1.x and 2.x meta is not updated within the msg which would be better for ZFS. What I am saying is msg per file which is not updated is better for snapshots. I belive 2.x version of single-dbox should be better (ie meta data is no longer stored with the msg) compared with 1.x dbox for snapshots. Cheers -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool fragmentation issues? (dovecot)
According to DoveCot Wiki dbox files are re-written by a secondary process. ie delete do not happen immediately, they happen latter as a background process and the whole message file is re-written. You can set a size limit on message files. Some time ago I email Tim, on a few ideas to make it more ZFS friendly. I.e. to try and prevent rewrites. If you use dbox and keeping snapshots you will eat your disk up. MailDir is a lot friendlier to snapshots, but it will be slower for backups or searching text within the body of lots of email. Ie there are pro’s and cons with ZFS. Personal I will go for snapshots as being more important as I take them about 10 times a day and keep them for 7 days. Also MailDirs are easier to restore and individual email. It comes down to pro’s and con’s. Unfortunate performance is always the most important goal. Cheers Damon. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool fragmentation issues? (dovecot) [SEC=UNCLASSIFIED]
> Got a link to this magic dbox format ? http://wiki.dovecot.org/MailboxFormat http://wiki.dovecot.org/MailboxFormat/dbox -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool fragmentation issues? (dovecot) [SEC=UNCLASSIFIED]
0n Thu, Jan 14, 2010 at 08:43:06PM -0800, Michael Keller wrote: >> The best Mail Box to use under Dovecot for ZFS is >> MailDir, each email is store as a individual file. > >Can not agree on that. dbox is about 10x faster - at least if you have > 1 messages in one mailbox >folder. Thats not because of ZFS but dovecot just handles dbox files (one for each message like maildir) better in terms of indexing. Got a link to this magic dbox format ? -Alex IMPORTANT: This email remains the property of the Australian Defence Organisation and is subject to the jurisdiction of section 70 of the CRIMES ACT 1914. If you have received this email in error, you are requested to contact the sender and delete the email. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool fragmentation issues? (dovecot)
> The best Mail Box to use under Dovecot for ZFS is > MailDir, each email is store as a individual file. Can not agree on that. dbox is about 10x faster - at least if you have > 1 messages in one mailbox folder. Thats not because of ZFS but dovecot just handles dbox files (one for each message like maildir) better in terms of indexing. The CPU stats for importing > 10 messages via imap copy are even more worse for maildir: dbox is about 100x more efficient... . But anyway: its no problem to test different with imaptest or offlineimap because each users mailbox (and even folders) could be stored in a different format... Just to clarify: I'm using dovecot 1.2.x -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] zpool fragmentation issues? (dovecot)
Any small updates to a file cause the file to be fragmented. The best Mail Box to use under Dovecot for ZFS is MailDir, each email is store as a individual file. Fair bit of statis info is kept in a index file, but also the filename it self is also used. The only problem with it is backups take longer as they are more smaller files (but this maybe better than what you are getting at the moment, if it is badly fragmented) See http://wiki.dovecot.org/MailboxFormat/Maildir http://www.linuxmail.info/mbox-maildir-mail-storage-formats/ The MailDir format will also work better with snapshots. Cheers -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
