Mail server slowness I

The University mail server began to timeout clients and slow down at approximately noon today. The cause of the problem is unclear.

The number of process running on the server appearred to be at a normal load average. The servers response from secure shell was slow. It appearred as though the system was having a problem allocating resources for the processes running, but memory and disk space were both available.

We shut down process to try and identify the cause of the slowness. Imapd and Ipop3d were disabled with no luck. The web server was shutdown, no luck. Then mailman and sendmail. At this point things improved.

I disabled the webmail interface and brought sendmail and mailman backup. I then brought the web server backup. The server still appeared to be responding in a slower than normal, but somewhat timely manner. I restarted the ipop3d daemon and about five minutes later the imapd daemon. The server still looked good–slower than normal, but somewhat timely. After restarting the webmail interface things when into the tank.

We tried restarting the webmail server between 3:00 and 3:30 pm, but the unbareable slowness remained.

We then rebooted the mail server at about 3:40pm.

The server was back to normal after the reboot.