[Imap-use] Intermittent Slow Downs

[Joel Zucker]

Hello,

Hoping someone can provide a little insight as to where I should be
looking for my solution.

I am running Squirrelmail 1.4.4 on Redhat Linux.
Using uw imap.

Problem is, most of the time my server is responding very fast and there
are no problems.  Every so often, for hours, the server slows way down
when trying to login to mail, or access folders via the squirrelmail web
interface (example: trying to view Inbox normally takes 1 or 2 seconds,
but during this slow down this same activity can take up to 30 seconds).
There is plenty of disk space available, and the system shows no unusual
load activity (vmstat 1). Mailq shows nothing too unusual either.  What I
do notice is that everytime I try to access a folder view the imap login
is what is taking sooo long (tailing my maillog).  Any functions in the
Squirrelmail interface that do not involve access mail files is very fast
during this time (ie. calendar view or todo list view).  I also noticed
that just trying to log into the server directly via ssh is very slow too.
I check DNS entries and everything seemed fine and fast there too.

Anyone have any ideas of what this might be?  It happened last night.  Not
sure if this is an every night thing, I'll be paying attention tonight.

Jz.