Recently the Data Protector support teams have seen issues where backups hang indefinitely. There is a known issue where if one of the clients in the backup specification is unresponsive due to resource issues such as out of memory/page file, CPU overload, excessive semiphores, etc., Data Protector will keep trying to get a response from the client and does not aborts or generate an error producing what appears to be a hang.
There is a fix available on Data Protector 9.08 for this issue which will generate an error and stop trying the unresponsive client.
If you believe that you are experiencing this issue please open a case with DP support and reference ID QCIM2A70610