Exchange 2007 SP1 is running on ESX3.5 VMware. (mailbox VM and HT/CAS running on another VM)
16 Gig Ram allocated to mailbox server
5 Storage groups
Runs GREAT for about one week then needs to be rebooted because of a memory leak?
This is most noticeable when the Backup Exec job that backs up the Storage groups fails. Event logs indicate that "The flush and hold operation for volume E: was aborted because of low available system memory."