timeouts when connecting to imap server

[Timo Veith]

Rudy Gevaert wrote:
> Some time ago we had some problems with sasl.  When to many users are
> connecting sasl starts blocking because it hasn't enough entropy.
> Recompile sasl so it uses /dev/urandom instead of /dev/random.

Hello Rudy,

thank you for your tip. I recompiled cyrus-sasl to use /dev/urandom 
whereafter I restartet cyrus. First it looked like timeouts were gone, 
because nagios reportet nothing. But then after a few hours the timeouts 
where back. :(

I also tried to raise the prefork number (0->1), but then my users told me 
that they could not connect to the pop server anymore. Others still 
could. Also the imapproxy didn't work anymore. I changed prefork back to 
zero and it was ok again.

What I haven't done before was raising the file descriptor limit. I read 
about the setrlimit -1 thing in the archive and remembered that I should 
be no problem. Anyway I raised the number from 1024 to 20480. Don't know 
if that will help but my feeling was that maybe cyrus is waiting 
somehow / somewhere because it cannot open anymore files and has to close 
some before. Just guessing ...

Any more hints?

Timo