While not entirely confident that we've found the root cause of performance issues on this server, we've been successfully mitigating them for several hours and we're still keeping an eye on it. At this point we don't think there's anything else that customers need to know.

SpamAssassin has been re-enabled for a bit. The Wednesday server is 100% operational at this time, the performance issues seem to be mostly limited to earlier in the day each day, as far as we can tell so far. So while we're not expecting a significant drop in performance right now, this status is remaining open as we're continuing to monitor the server and try to get a handle on just what needs to be tackled next.