[Dovecot] Dovecot very slow on a mailbox with > 700 IMAP Folders

[Timo Sirainen]

On Thu, 2011-05-05 at 10:44 +0200, Timo Sirainen wrote:

> Ah, you have ACLs enabled. With ACLs it's looking up dovecot-acl file from each folder before returning it. This shouldn't be necessary with LSUB I think. I suppose some kind of an ACL cache could be a good idea some day too. And maybe a setting not to bother looking up ACLs for mailboxes in private namespaces.

http://hg.dovecot.org/dovecot-2.0/rev/a7f1980d250c should help for your
specific problem.