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AlGon's avatar
AlGon
Level 6
13 years ago

Erase tapes used by Backup Exec

 

 

Netbackup 7.1.0.2

Windows 2003 Server

Hi,

We've migrated a number of servers over to Netbackup from Backup Exec.  We would like to re-use some of the tapes used by Backup Exec.

I run a quick erase on each tape so that it can be used by Netbackup.   

After Netbackup has used the tapes for backup jobs and when the tape is marked as full, the amount of data that's been written to the tape is not only no where near the maximum compressed size but, in some cases, it's no where near the uncompressed size.

Is this due running a quick erase instead of a long erase?   

Is this the best way to prepare a tape for use by Netbackup if it's already been used by Backup Exec?

Cheers

7.1.x and Earlier
Backing Up
Backup and Recovery
NetBackup
  • Mark_Solutions's avatar
    Mark_Solutions
    13 years ago

    This may be valid and not valid images

    If the tapes stay in the library for a while it can be the case that the first few hindgred GB have expired and are no longer valid, but the last 215GB are still valid

    Being tape it cannot overwrite the expired data at the start of the tape it just has to wait until the tape is either full and becomes available once all data has expired, or the tape is not used for a while and then alld ata expires

    Hope this makes sense

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  • Yogesh9881's avatar
    Yogesh9881
    Level 6
    13 years ago

    1. insert media in robot

    2. take inventry

    3. go to media & point to newly added media and re-label it

    4. Relabel it. as mentioned in below

    Right click the media and select label.

    there is a tick box that says something like "verify media label before performing operation", you need to untick this.

  • Yasuhisa_Ishika's avatar
    Yasuhisa_Ishika
    Level 6
    13 years ago
    Tape capacity is varied depending on the hardware compression ratio of data. Compression ratio will become near by 1:1 when data is hard to compress(typical with already compresses data like .zip/.gz/.jpg/etc... or random binary data). If the capacity you got is too small against tapes native(uncompressed) capacity, it must be problem. Otherwise, in most case, it is because of data tendency. To reuse tape, re-labeling is enough, I believe.
  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    If in your Media Servers host properties - Media Section you have selected to overwrite BE-MTF1 media then you do not need to do anything.

    NetBackup will pick up the tape, notice that it is Backup Exec media and automatically label and overwrite it.

    The capacity of data going to the tape will not be directly governed by NetBackup itself and if you are not getting what you expect then the may be a fault with the tape or tape drive but if you getting native or above native data amounts then you do not have a lot to go on.

    Hope this helps

  • AlGon's avatar
    AlGon
    Level 6
    13 years ago

    Great.

    This sounds like a good solution, I'll give this a go.

    Is it possible the when I've done a quick erase on a tape, that has backup exec media on,  Netbackup isn't writing from the start of the tape?

    Cheers

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    No - a tape is a tape - so an erase erases the header on the tape and it finishes when the tape reports it end of tape marker

    I cannot see anything that you have done will affect its capacity

  • AlGon's avatar
    AlGon
    Level 6
    13 years ago

    Hmm, this is my bad.  I ran the report to show tapes written between a certain time period which wasn't showing me the total amount on the tape, oops.

    Anyway, thanks to everyone for the responses. Mark, I'm going to put your solution in place so we don't have to manually erase these tapes.

    Cheers

  • AlGon's avatar
    AlGon
    Level 6
    13 years ago

    I must be going mad.

    I've compared the tape written report (set it to go back to the beginning of time ;)) with the reported size of data on the tape (by adding the kilobytes column on the volume pool) and they don't always match.

    The tape written report is showing one tape to have written 215GB.  The KB column in the volume pool is showing the very same tape having 1.2TB on it.  What's this all about then?

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    This may be valid and not valid images

    If the tapes stay in the library for a while it can be the case that the first few hindgred GB have expired and are no longer valid, but the last 215GB are still valid

    Being tape it cannot overwrite the expired data at the start of the tape it just has to wait until the tape is either full and becomes available once all data has expired, or the tape is not used for a while and then alld ata expires

    Hope this makes sense

  • AlGon's avatar
    AlGon
    Level 6
    13 years ago

     

    So quite possibly these tapes were left in the library from before, the backups at the weekend have run using the same tape.  

    The previous images expired half way through the backup job but because the backup this weekend had already started before the images expired then it appended to the remainder of the tape and filled it up quickly.  

    Is there a report we can run or a way we can prove this happened?

    Many thanks for all your help Mark.  I have marked your answer as the solution.