I am running Exchange 2010 on a VM with 4 cores, 16GB RAM, and on Server 2008 R2. We migrated from Exchange 2003 about 5 months ago. For about 2 months now we've been having to reboot the server because the lsass.exe process takes up all the CPU. The only way we could clear it was to reboot. This put us back to normal for a few days then the lsass process would start to spike. It would spike then return to normal, and keep doing that through out the day. I tracked the process looking for a pattern. At first there wasn't one, but after a few days of tracking a pattern emerged of spiking every 20 minutes.
I came in this morning and the process was locked in a high CPU usage for 5 hours until I had to reboot again. Anyway, I'm at a loss as to what to do now. It's a real pain rebooting this thing every week.
Any ideas?