Since I installed roundcube a year or so ago, the performance in general has been subpar and I was having issues where apache threads were pegging the cpu to 100% consistently. I had the pam errors in messages, and all the typical complaints people make when using UW-imap with roundcube. Load avg on my server was typically between 2-3.
I tracked the problem down to how roundcube interfaces with UW-imap. The combination of the two are just a no-no. UW-imap is fine with squirrelmail, and roundcube is fine with other imap servers, but put the two together and HORRIBLE HORRIBLE performance.
I switched to dovecot from UW-imap today, and all my problems appear to be solved. The server flies and load avg is down to .2 to .4!
Additionally. . dovecot is super-easy to install. Took me about 1 hour start to finish including cert creation and it was my first time using it.
If you're using UW-imap with roundcube, stop waiting for "the next release" to fix it. Just give up and go dovecot
-Rich
