V S Rao
2009-May-24 18:13 UTC
[Dovecot] Dovecot Max Connections & mbox vs. maildir format - Recommendations?
>> I had big issues with timeouts until I realize the the imap and mbox format >> isnt a good choice if your users have huge naiboxes. >> At my server there were users with mailboxes arount 700MB to over 1GB. each >> time one of those users checked their email >> the imap server had to open this huge file and parse it, causing I/O issues.>> The only solution I found it was switch from mbox format to maildir format.I am changing the subject line to reflect the discussion. I too have a similar case with large mailboxes. My user mix is 70% POP3 vs. 30% IMAP. Would maildir still be the best recommended format? What is the opinion of the experts here? The reason I am asking is that I am preparing to upgrade my mail server to RHEL 5.3. That would mean my Dovecot will be atleast 1.0.7, which should not be bad. If the recommendation is that I go from mbox format to Maildir, I want to plan that as well. However I don't want to land up in a situation where, I have to move back from Maildir to mbox again. So please do advice me on the best. BTW one question: Assuming that my server has enough resources, ( 8 CPU @ 3.0GHz, 8GB RAM, 2Gbps FC Storage directly attached to the server & Gigabit NIC) what is the maximum number of concurrent connections that Dovecot can handle POP3 + IMAP combined? And I am asking for all the processes combined: POP3-login processes IMAP-login processes POP3 sessions IMAP sessions Any TCP/IP kernel parameters to be tuned? or maybe in dovecot.conf? Any advice will be immensely valuable to me while doing the migration. Thanks and Regards V S Rao
Roy Sigurd Karlsbakk
2009-May-24 18:23 UTC
[Dovecot] Dovecot Max Connections & mbox vs. maildir format - Recommendations?
On 24. mai. 2009, at 20.13, V S Rao wrote:> I am changing the subject line to reflect the discussion. > > I too have a similar case with large mailboxes. My user mix is 70% > POP3 vs. 30% IMAP. Would maildir still be the best recommended > format? What is the opinion of the experts here? > > The reason I am asking is that I am preparing to upgrade my mail > server to RHEL 5.3. That would mean my Dovecot will be atleast > 1.0.7, which should not be bad. If the recommendation is that I go > from mbox format to Maildir, I want to plan that as well. However I > don't want to land up in a situation where, I have to move back from > Maildir to mbox again. So please do advice me on the best.IIRC RHEL only supports EXT3, not XFS/JFS and so on. ext3 is nice with large directories only if dir_index is enabled (tune2fs -O dir_index / dev/something). If dir_index is not enabled, ext3 will perform quite terribly with some 1000+ files in a directory. Apart from that, I would guess maildir would be best both for IMAP and POP. roy -- Roy Sigurd Karlsbakk (+47) 97542685 / 98013356 roy at karlsbakk.net http://blogg.karlsbakk.net/ -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et element?rt imperativ for alle pedagoger ? unng? eksessiv anvendelse av idiomer med fremmed opprinnelse. I de fleste tilfeller eksisterer adekvate og relevante synonymer p? norsk.