I have exchange 2013 running on windows server 2012. The mailbox database which is only about 25 GB in size keeps dismounting on it's own. The only events I see in the log are
At '6/13/2013 11:22:43 AM' database copy '#######' on this server appears to have an I/O error that it may be able to repair. To help identify the failure, consult the Event log on the server for other storage and "ExchangeStoreDb" events. Service recovery was attempted by failover to another copy. The failover was unsuccessful in restoring the service because of the following error: 'There is only one copy of this mailbox database (########). Automatic recovery is not available..
At '6/13/2013 11:22:46 AM', the copy of database '########' on this server encountered an error during the mount operation. For more information, consult the Event log on the server for "ExchangeStoreDb" or "MSExchangeRepl" events. The mount operation will be tried again automatically.
