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BXEC2014: Backups in same tape has different expiration date

kha
Level 4

I have a media (tape) set with one tape in it.

This media set has overwrite protection period = 25 weeks, append period = infinite - allow append.

  • The backups made on 18/26/16 and 9/23/16 said expired, while the backups made on 8/14/14 says expire on 11/26/2061 and backups made 0n 7/22/2016 says expire on 7/22/3016

The backup expiration date are all over the place in this same backup tape.  I wonder why that is the case and how can i change them to have the same backup expiration date if possible?  My goal for the backup sets in this particular tape is to keep all the backup sets until they're approved to be deleted, no automatic overwritten.

 

 

1 ACCEPTED SOLUTION

Accepted Solutions

Colin_Weaver
Moderator
Moderator
Employee Accredited Certified

Tape sets do not actually expire as unlike disk sets they are ONLY removed from the system when a complete tape is overwritten (or erased/deleted). We cannot change the displayed dates against backups sets from an earlier writing of data to the same tape just because you have written more data to the tape which has moved the overwrite period away in time as this expiry date for a backup set is ONLY generated at the time of the specific job and is not touched by later jobs.

As such the visible expiry date against a Backup Set that is held on tape should be ignored (apart from as a guideline) and you should ONLY use the Overwrite Protected Until dates/times as an indication of when a tape can be overwritten.

You should perhaps also be aware that you cannot overwrite only part of a tape, you can ONLY overwrite the whole tape. Making the Overwrite Protected Until date being the correct date to use when trying to manage tape usage (which is of course completely different from managing disk usage because disk sets can be individually reclaimed)

Oh and there is NO automatic deletion of data on tape (like there is on disk) - an overwrite operation has to take place and that only happens when the tape is overwritable and when a backup job runs that needs an overwriteable tape (or if you manually erase the tape). Similarly if the tape is not mounted in a drive, irrespective of the overwrite protection it cannot be overwritten and the data is retained.

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1 REPLY 1

Colin_Weaver
Moderator
Moderator
Employee Accredited Certified

Tape sets do not actually expire as unlike disk sets they are ONLY removed from the system when a complete tape is overwritten (or erased/deleted). We cannot change the displayed dates against backups sets from an earlier writing of data to the same tape just because you have written more data to the tape which has moved the overwrite period away in time as this expiry date for a backup set is ONLY generated at the time of the specific job and is not touched by later jobs.

As such the visible expiry date against a Backup Set that is held on tape should be ignored (apart from as a guideline) and you should ONLY use the Overwrite Protected Until dates/times as an indication of when a tape can be overwritten.

You should perhaps also be aware that you cannot overwrite only part of a tape, you can ONLY overwrite the whole tape. Making the Overwrite Protected Until date being the correct date to use when trying to manage tape usage (which is of course completely different from managing disk usage because disk sets can be individually reclaimed)

Oh and there is NO automatic deletion of data on tape (like there is on disk) - an overwrite operation has to take place and that only happens when the tape is overwritable and when a backup job runs that needs an overwriteable tape (or if you manually erase the tape). Similarly if the tape is not mounted in a drive, irrespective of the overwrite protection it cannot be overwritten and the data is retained.