[Dovecot] Restarting dovecot-auth stops authentication

Attila Nagy bra at fsn.hu
Tue Dec 21 20:13:54 EET 2010

  On 12/21/2010 06:41 PM, Timo Sirainen wrote:
> On 21.12.2010, at 19.37, Attila Nagy wrote:
>>>> service imap-login {
>>>>   client_limit = 8
>>> Why imap-login with this small client_limit? The default should be ok (1000).
>> Because I think that Dovecot's processes block on IO and not just on distinct IO operations, but larger tasks, like opening a maildir with a lot of e-mails without indexes.
> *-login processes do no disk I/O.
Oh, I've had problem with authentication previously, and that stuck. 
Removed, thanks for noticing.
>> Am I wrong? Or partly wrong, because it uses blocking IO, but it can multiplex them, so while one user struggles with the file system to build indexes of his maildir, an other client in the same process can happily do POP/IMAP stuff?
>> The rationale is to spread IO (and users) amongst processes, because the OS can schedule them concurrently, but don't have too many processes, because that eats a lot of memory and other resources.
> This applies to imap/pop3 service, and that's why only client_limit=1 works well with them for now.
Apart from these errors, it works fine. It would be interesting to see a 
response time statistics for both settings, to see how worse it gets 
with raising client_limit.

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