Slow connections to imapd *Urgent* - Update

[Russell Gnann]

The only clients that connect using IMAP are the web cleints our users use,
and which we built.  I don't see how there could be a DNS issue here since
all host names resolve properly forward and back on both the IMAP server and
the clients.  We finally determined that for some still unknown reason the
master process was unable to fork imapd processes beyond 6-8.  This was
causing the backlog q for our network interface to stay constanly full.  Our
current work around to perfork 100 imapd processes which for the time being
seems to have fixed the connection issue.  

We are still investigating why the master process suddenly would be unable
to fork imapd properly when it has been working fine upto this point.

_______
Russell Gnann
UNIX Systems Administrator
Andrx Corp.



-----Original Message-----
From: Peter Lawler [mailto:green_eggs_and_spam at six-by-nine.com.au] 
Sent: Sunday, February 16, 2003 5:01 PM
To: info-cyrus at lists.andrew.cmu.edu
Subject: Re: Slow connections to imapd *Urgent*


Roland Pope wrote:
> ----- Original Message -----
> From: "Russell Gnann" <rgnann at corp.pol.net>
> To: <info-cyrus at lists.andrew.cmu.edu>
> Sent: Saturday, February 15, 2003 3:51 PM
> Subject: Slow connections to imapd *Urgent*
> 
> 
> 
>>As of today we have been experiencing extremly slow connections to our
> 
> Cyrus
> 
>>IMAP server.  So far we have been unable to detemine any cause.
<snip>
> 
> DNS lookups are frequently the cause of this sort of problem. I would 
> make sure you can access DNS from the server, and that you can resolve 
> the IP addresses of the incoming clients.
> 
> Roland

Yeah, this was my thought when I read the original post.

The poster may like to check their patching levels. You may also wish to 
try truss(1)ing the master process with timestamping and tracing forks, 
only after it's slowed down (to reduce noise in the logfile), to see 
where things are slowing up.

Pete.