scratch issue

[arjun7]

in my library 3 tapes are there In scratch volume pool. when backups are running the tapes are goes to frozen state. then I unfreeze all those tapes and restart the backup.. again tapes went to frozen state but the tapes volume pools is changed from scratch to daily volume pool.

at the time I have unfreeze the tape and expire it and the move to scratch pool and run the label command and restart the backup.. some tapes are used for backups but some tapes are again  goes to frozen state..

for this what is the exact solution.. plz help me 

[Marianne · Accepted solution]

You need to find out WHY tapes are getting frozen - not just unfreeze them.
There are MANY reasons why NBU will freeze media:
write protected tapes used for backups
3 I/O errors in 12 hours
Certain hardware TapeAlert errors reported by the tape drive firmware
etc, etc.

As a start, you can run Media Logs report and select a period that will cover the issue.

In the report, use the 'Filter' function to exclude 'Info' in Severity column. This will leave you with Warning and Error messages. 
This will enable you to find the error causing tape to be frozen.

For further troubleshooting, create bptm log folders on all media servers.
Also add VERBOSE entry to ..volmgr\vm.conf file on all media servers and restart NBU.

Job Details will tell you which media server was trying to write to the tape.
Check bptm and System logs on media server for errors.