I have a server that has been running qpopper and sendmail on RH8 for
several years. I am having a problem where qpopper logins can take 15-20
seconds to authorize at peak usage times. Yet I look at the server and
neither CPU nor memory are maxed out. Load average might be up to 4 or 5
when this occurs. Also, if I try to telnet or ssh to the server while this
is occuring, often I will see a quick prompt for username/password, but then
the same wait for auth to complete.
I believe the server is a 1.26GHz Xeon with 2GB memory and a RAID5 array of
3x18GB 10K SCSI drives.
This is almost certainly a PAM question not specifically a Qpopper question,
but I'm hoping someone can point me in the right direction. I don't see any
configuration that would limit PAM to a certain number of logins per second
or something like that, so I'm stumped why the auth process gets bogged down
when the server seems to be working hard but not by any means overloaded.
I have a newer server running the same configuration on dual 2.4GHz Xeons
with a SATA drive and I'm not seeing the same issue, but that may be due to
different users rather than different server.
