I now have Dovecot in production and things are apparently trouble-free. The one known problem is that initial client inbox load can take 30 seconds - 2 minutes. For instance: 'I got fed up waiting and went and got coffee'...this with a 3MB mbox inbox...and my mail server is a substantial machine consuming 25% CPU just for this person's IMAP session. I realize that a certain amount of performance piggishness is inevitable with large mbox inboxes (the prize goes to the user with a 500MB inbox). Eventually, I plan to move to maildir format, but for now I'm here. Also, we have legacy requirement for procmail, so I can't currently use deliver. Questions: 1) Any tuning I can do to improve this? 2) Any metrics, troubleshooting I should be doing to better characterize the problem? -- ===Stewart Dean, Unix System Admin, Henderson Computer Resources Center of Bard College, Annandale-on-Hudson, New York 12504 sdean at bard.edu voice: 845-758-7475, fax: 845-758-7035
* Stewart Dean <sdean at bard.edu>:> I now have Dovecot in production and things are apparently trouble-free. The > one known problem is that initial client inbox load can take 30 seconds - 2 > minutes. For instance:Initial? Initial after what? I guess the index is being rebuilt, cold that be?> 'I got fed up waiting and went and got coffee'...this with a 3MB mbox > inbox...and my mail server is a substantial machine consuming 25% CPU just > for this person's IMAP session.Normal.> I realize that a certain amount of performance piggishness is inevitable > with large mbox inboxes (the prize goes to the user with a 500MB inbox). > Eventually, I plan to move to maildir format, but for now I'm here. Also, > we have legacy requirement for procmail, so I can't currently use deliver. > > Questions: > 1) Any tuning I can do to improve this?Use deliver to rebuild the index wehenever a mail is delivered. -- Ralf Hildebrandt (Ralf.Hildebrandt at charite.de) plonk at charite.de Postfix - Einrichtung, Betrieb und Wartung Tel. +49 (0)30-450 570-155 http://www.arschkrebs.de "The percentage of users running Windows NT Workstation 4.0 whose PCs stopped working more than once a month was less than half that of Windows 95 users."-- microsoft.com/ntworkstation/overview/Reliability/Highest.asp
On 19.7.2007, at 18.23, Stewart Dean wrote:> I now have Dovecot in production and things are apparently trouble- > free. The one known problem is that initial client inbox load can > take 30 seconds - 2 minutes. For instance: > 'I got fed up waiting and went and got coffee'...this with a 3MB > mbox inbox...and my mail server is a substantial machine consuming > 25% CPU just for this person's IMAP session.That sounds too much. Dovecot should take about the same time as UW- IMAP when initially opening the mailboxes.> 1) Any tuning I can do to improve this?http://wiki.dovecot.org/PerformanceTuning has some suggestions.> 2) Any metrics, troubleshooting I should be doing to better > characterize the problem?Can you easily reproduce this with any mbox file that's a few megabytes large? Does deleting Dovecot's indexes and immediately reopening the mailbox take as long? So does disk I/O have anything to do with the wait, or is it just CPU? -------------- next part -------------- A non-text attachment was scrubbed... Name: PGP.sig Type: application/pgp-signature Size: 186 bytes Desc: This is a digitally signed message part URL: <http://dovecot.org/pipermail/dovecot/attachments/20070719/603696e0/attachment-0002.bin>