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.
