timeouts when connecting to imap server

[Rudy Gevaert]

Timo Veith wrote:
> Hi list readers,
> 
> I have a problem with our imap server. My users complain about timeouts 
> when connecting to the server. We have nagios checking the status of the 
> imap port. Most of the time it reports success and response times of less 
> than one second. But sometimes the response takes longer than 10 seconds 
> and then nagios reports a timeout. 
> 
> I don't think that the machine is overloaded, it's a dual xeon 2,8 ghz 
> with 4 gb of ram and a gigabit link.
> 
> I am running Gentoo Linux with gentoo-sources as kernel (version 2.6.18), 
> cyrus-imapd-2.2.12-r4 (autocreate patch applied). I have no iptables 
> rules activated.
> 
> Because nagios just connects and disconnects right away, I don't think 
> that the problem has something to do with authentication. However I am 
> using saslauthd -> pam -> pam_ldap -> Active Directory. 
> 
> How can I find out what cyrus is doing right at the time when those 
> timeouts happen or where the thing is hanging?

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.

Rudy

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Rudy Gevaert          Rudy.Gevaert at UGent.be          tel:+32 9 264 4734
Directie ICT, afd. Infrastructuur  Direction ICT, Infrastructure dept.
Groep Systemen                     Systems group
Universiteit Gent                  Ghent University
Krijgslaan 281, gebouw S9, 9000 Gent, Belgie               www.UGent.be
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