We are having some issues with clients getting Transaction Timeout when connecting to our clustered SQL Server 2008 R2.
To investigate the problems I have been digging into sys.dm_tran_active_transactions and a few times I saw rolled back transactions being there up til 4 hours after they were rolled back(After four hours the IIS webserver that started the transaction were restarted and they dissappeared), this was non-DTC transactions even though we do have DTC transactions as well.
So when can I expect committed/rolledback transactions to be cleared out of sys.dm_tran_active_transactions and if it is supposed to happen immediately what kind of issues could keep them "hanging" there.