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This is a commonly reported problem in Netvault Backup and is invariably caused by a configuration issue.
The problem can be presented in a number of ways, but the common denominator is that a tape is not reused when the backup operator believes that it should be. A related issue is that tapes appear as 100% full while the contents appear to be much smaller.
There is no simple fix for this, as there are many permutations of the problem, so it is important to understand the underlying concepts of backup lives, tape and saveset expiry.
Overview.
The re-use of media (ie physical or VDL tapes) within Netvault is controlled by the target and advanced options of the jobs that write to the tapes. Each job writes its data in logical units called "savesets". Each saveset has a defined backup life which is configured in the advanced options tab. Information pertaining to the backup life is retained in the Media database until the saveset expires (i.e. reaches the end of its backup life). Once all the savesets on a tape have expired, the tape is “marked for reuse” by the media manager.
Important Note:
The most important thing to note here is that a tape cannot be reused until ALL the savesets on the tape have expired. Tape is a serial media and it is not possible to "fill in" gaps on tape, we can only append to the end of the tape. VTL mimics physical tape and is subject to the same limitations.
Job Target set "Reuse media" option:
Jobs also have a target definition option of "reuse media" which controls whether or not they will use tapes that have been "marked for reuse" by the media manager on the expiry of all the savesets.
Please note that for a tape to be reused two elements must come together:
1) ALL the savesets on the tape mus have expired
2) the tape mist meet the criteria of a media request
Remedial Action
In order to ensure that tapes are available to be overwritten, the jobs that have savesets on the tape that have not expired must be edited to make sure that the advanced options are set correctly. Note that amending the jobs will only affect savesets written after the amendment, any existing savesets with incorrect expiry dates will have to be removed manually through Media Management.
In the short term, a tape can be blanked or manually marked for re-use, but this will not address the underlying problem of incorrectly configured jobs.
Troubleshooting Notes:
1) Have the savesets for the tape expired?
2) For scheduled jobs will any remaining unexpired savesets expire BEFORE the job tries to reuse the tape?
3) Has the tape been rescanned? Rescanning a tape will temporarily bring back all the savesets into the media database for a default time period of 24 hours (for time based backup life tapes).
Media Problems: tapes cannot be overwritten.
