Yesterday I experienced some serious performance problems with Cyrus-imapd.
My INBOX contains about 2500 messages, and accessing it through Squirrelmail took my browser about ~120 seconds to display the overview page.
I found out that performance problem was caused by the imapd process which was causing a lot of iowait. The iowait was caused . . . → Read More: Cyrus-imapd i/o performance (100x speedup)