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raj08's avatar
raj08
Level 4
14 years ago
Solved

Scratch Tapes and Quick Erase in VTL

Hi,

I have this question about VTL. Usually when we move scratch tapes between Robots, we ususally select the required scratches and perform 'quick erase' and then move it to another TLD. I have the below questions regarding this.

1. What is the exact function of 'Quick Erase' and what are all the other operations simillar to that (like long erase)?

2. What will happen, if I don't quick erase the scratch tapes and move it directly to other TLD?

3. Is it mandatory to do a quick erase before moving tapes between VTL? Wouldn't it automatically erase data when moving a tape from library to scratch?

 

Thanks.

RAJ

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  • mph999's avatar
    mph999
    14 years ago

    OK, now I understand.

    No need to erase is the basic answer.  NBU actually relabels tapes when it resuses them.

    I think as it seems you are in the same environment, there is no need to worry about relabeling tapes manually.  Just try it, it will soon be clear if there is any issue.

    Scratch tapes ...

    A pool that is defined as scratch (but can have any name you want, apart from NONE, is simple a pool that contains media available for use.  Any other pool required a media will move one from scratch.

    As Marianne points out, some VTLs require scripts / procedures to reclaim disk space - the VTL vendor will advise when this is required.

    Martin

5 Replies

  • mph999's avatar
    mph999
    Level 6
    14 years ago

    Quick erase I belive just overwrites the media header

    Long erase, I believe is tape drive manufacturer dependant.  I've never run it, but was told by a backlline engineer that on some drives, it won't do anything.

    DISCLAIMER - I'm only the messenger ...

    Onto point 3.

    Exactly how are you going to move a tape from one VTL to another ???  It is virtual, it does not actually exist !

     

    Lets make them real tapes - if you are moving tapes from one library to another, there is no need to erase.

    Depending on the config of 1. the libray and 2. NBU (if moving to another environment) you might need to re-label, and, when doing so deselect the option to validate the media header.

    Martin

  • raj08's avatar
    raj08
    Level 4
    14 years ago

    Thank you martin. Still I didn't get the clear idea. I might have not given the details clearly.

    2. In VTL, I am moving the Media (Virtual Tapes) say, from TLD0 to TLD1. What I do is, export the media from TLD0 to vault and import from valut to TLD1. so, before exporting from TLD0, I always perform 'quick erase' on the media (eventhough it is in Scratch pool).

    Hence I would just like to know, if erasing the media is just a best practise or a mandatory thing to do before moving to other Robot.

     

    3. I just want a general idea on how Scratch tapes works? Am using NBU 7.1. So once the media expires, would it automatically erase the data in media and put it in scratch pool? Or It requires manual quick erase?

    If the answer is differs from environment to environment, where do we check this setting?

     

    Thanks Again.

     

     

  • Marianne's avatar
    Marianne
    Level 6
    14 years ago

    There is no requirement in NetBackup for quick erase when tapes are moved.

    If it is required by the VTL to reclaim the disk space, it is probably a VTL (not NBU) requirement. Speak to your VTL vendor.

  • mph999's avatar
    mph999
    Level 6
    14 years ago

    OK, now I understand.

    No need to erase is the basic answer.  NBU actually relabels tapes when it resuses them.

    I think as it seems you are in the same environment, there is no need to worry about relabeling tapes manually.  Just try it, it will soon be clear if there is any issue.

    Scratch tapes ...

    A pool that is defined as scratch (but can have any name you want, apart from NONE, is simple a pool that contains media available for use.  Any other pool required a media will move one from scratch.

    As Marianne points out, some VTLs require scripts / procedures to reclaim disk space - the VTL vendor will advise when this is required.

    Martin