Drive goes down sometimes

Hi,

Often the policy NDMP runs and fails with error code 2009, i.e. drive down. As soon as it starts the drives go down. It is rerun and then it runs fine.

But why it fails at that time when it is scheduled. Many times it runs good and sometimes it fails with 2009.

Also to check logs there is no folder bptm in  netbackup/logs. If it is due to specific tapes then where to check for logs because the entry has been deleted from activity monitor. 

Please suggest.

One more thing if entry has been deleted from activity monitor then can we get it back or check somewhere else because KEEP_LOGS_DAYS is set to 192 hours.