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after backup expire no free space available on tapes

mnakhan
Level 5
Partner Accredited Certified

HI,

i take multiple backups of  file system on tape and each backup retention is two week. manually expire it first backup and check the use sapce on tape is remains the same.

Kindly guide me how i release its space after backup expire.

regards.

1 ACCEPTED SOLUTION

Accepted Solutions

StefanosM
Level 6
Partner    VIP    Accredited Certified

the tape is a serial medium. You can not free up space from the beggining, only appent to it.

to reuse a tape, all backups on the specific tape must be expired (manualy or automaticaly by netbackup when the expiration date comes). As your retention is two weeks, the tape will be usable again after two weeks counting form the date of the last backup written on it.

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7 REPLIES 7

StefanosM
Level 6
Partner    VIP    Accredited Certified

the tape is a serial medium. You can not free up space from the beggining, only appent to it.

to reuse a tape, all backups on the specific tape must be expired (manualy or automaticaly by netbackup when the expiration date comes). As your retention is two weeks, the tape will be usable again after two weeks counting form the date of the last backup written on it.

mnakhan
Level 5
Partner Accredited Certified

i take a backup on date 27th may 2014 and its retention is  two week i.e expire on 10th june 2014. if before going to expire the backup on date 5th june 2014 i change its retention from two week to one week and then mark it expire.  will i free up the sapce on tape before two week?

RonCaplinger
Level 6

You cannot "free up the space" on a tape by expiring images, you can only expire ALL images on it in order to reuse it.  However, you have a retention period of two weeks for a reason, and you should NOT expire data manually unless you have a very good reason.  If the only reason is you want more space on tape, I would recommend you buy more tapes. 

As Stafanos already mentioned, tape cartridges are serial storage, unlike disk which can be read, written, and deleted randomly.  You can add backup images to a tape (until it is full), but you will never be able to expire individual images on a tape to make room for more images.  This is how NetBackup works and it is by design.

Nathan_Kippen
Level 6
Certified

Once your tape does expire you can send it back to the "scratch" pool

 

bpexpdate -deassignempty

 

Searches the catalog for the removable media that no longer contain valid backups. It removes the media from the media catalog and removes the media IDs in the Media Manager catalog. The media is then available to use again. You can use the NetBackup Images on Media report to determine if the assigned media no longer contains valid backups.

 

 

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

Only when ALL images on a tape has expired can it be overwritten from the beginning.

See this excellent blog: 

Understanding how NetBackup writes to a tape. 

Jim-90
Level 6

On VTL "tapes" to free up space I do a force expire if it contains active backup images.  This will put it back in the SCRATCH pool.  When in the scratch I do a "quick erase" and that will free up the capacity used by the VTL "tape".  In the world of physical tapes it is the same process except the when you do a quick erase all you are doing is blowing away the tape header when that goes there is no reference left of its previous life in NetBackup.

jim_dalton
Level 6

Why do you want to erase anything? Totally unnecessary. Once a tape is scratch, it'll go back in the scratch pool available for use. The data will still be there up to the point when the tape IS re-used. Can be handy ...

Jim