I am going to provide as much detail as possible.
We have a windows server 2003 r2 with service pack 2 installed. We use Veritas Backup Exec 9.1 Small Business for windows server edition to backup our data every night. Before the beginning of this month, the Backup job was set up to backup all of the exchange data by which we had selected "Microsoft Exchange Mailboxes","Microsoft Exchange Public Folders", and "Microsoft Information Store" from the backup list. We are also backing up various file directories including a very large folder containing about 70 GB of pdf files. The majority of these files were on the local machine that is connected to the backup tape robotic library. The backup takes up on average 140 GB. As of this month we have started using sql server (not sure if that has anything to do with it) and have moved the directory full of pdf files to another server. We have modified the backup jobs accordingly. Now every once in a while, while our backup is running, around 2:00 AM (backup starts at 1:00 AM) the server supposedly (nobody is here) restarts and when it comes back up it is in a non-workable state. The servers raid is solid and the screen is usually at the ctrl-alt-del screen and will not unlock no mater what keys are pressed. usually restarting this server solves the issue but we have had one instance where we had to restart the server 3 times in order for it to get back up and running properly. To me this sounds like some type of exchange problem to me because the only thing in the system logs are messages about the exchange data store online de-fragmentation and deletion of old mailboxes. I don't see any other kind of errors in here.
Can anyone help me?