[Dovecot] Migration questions...

[Seth Mattinen]

Phillip Macey wrote:
> On 14/05/2009 5:11 PM, Steffen Kaiser wrote:
>> On Wed, 13 May 2009, Richard Hobbs wrote:
>>> The main complaint we have from users is that their IMAP Inbox, with
>>> 5000 emails in it takes ages to appear, and no amount of coaxing will
>>> convince them to split their inbox into multiple folders.
>>
>> Oh, we serve Maildir via Dovecot IMAP and 5000 messages per folder are
>> a wimp. Problems start if the user:
> We are having some performancec issues on our server at the moment - all
> I can put it down to is the large size of some maildirs. Eg. `ls -ld
> Maildir/cur` might show a directory >20Mb in size for some of our users
> (20-30k emails).
> (Performance issues == everything is running ok then all of a sudden
> load avg goes through the roof, system cpu time goes crazy. Reading mail
> grinds to a halt. Then everything recovers just as suddenly and the load
> avg gradually returns to normal levels)

Are you using ext3 by chance? Vanilla ext3 without directory indexing
(or whatever it's called) *hates* directories with a lot of files - like
maildir. Personally, I use XFS, which doesn't suffer from this problem
since it uses b-trees instead of a table(!) like ext3 does.

~Seth