I have a Zimbra (OpenSource 4.5.4 on RHEL4) that decides to use all remaining CPU power. I first thought it was doing some re-indexing, but this comes back every several days and goes on for at least the whole day (XEON, 3Gb). Meanwhile the mailboxes can not be accessed, but all incoming mail is handled as expected.

I disabled and unloaded logger (as suggested in MySQL CPU Usage, but that doesn't change anything.

Any suggestions on what is going on and how to resolve this?