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available_media showing that tape is full but the report showing its not full

Zahid_Haseeb
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Problem

i am using a tape cartridge with 4mm density and a size of 36/72(compress) GB. I took backup of all data in compress form. Problem is my available_media command saying that the tape cartridge is full but the report which i shared is saying that tape have around 25GB.  As i said that my Tape have a capicity of 36/72GB

 

Environment

Netbackup = 7

OS of Netbackup = win2003R2

 

C:\Program Files\VERITAS\NetBackup\bin\goodies>available_media.cmd
media   media   robot   robot   robot   side/   ret    size     status
 ID     type    type      #     slot    face    level  KBytes
----------------------------------------------------------------------------
CatalogBackup pool


DataStore pool


NetBackup pool

311010  4MM      NONE     -       -      -       9     36200115 FULL

None pool


 Reports

1 ACCEPTED SOLUTION

Accepted Solutions

Marianne
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Zahid, have another look at your 'Tape List' report:

There are 24 Images on tape, of which  23 are Valid images. These 24 images are totalling 36200115.

Any other report will simply report on the 23 Valid images. You will best know why there is a difference between number of images and valid images (could be a failed backup in the middle of a multiplexed backup or an image that you have expired).

Fact is, you have one INVALID image that is occupying space on the tape. As you know by now, backups to tape are written sequencially. No backup application can reclaim/overwrite invalid/expired data in the middle of a tape.

Media marked as FULL means that 'End of Media' was reached while a backup was written. This is not a NetBackup 'decision', it is a physical state encountered by the hardware. You will be able to see this in bptm log.

View solution in original post

9 REPLIES 9

Zahid_Haseeb
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I have also attached two reports of snap in attachment for reference.

Andy_Welburn
Level 6

can be dependant upon the type of data that is backed up.

My response below was to a similar query on the Backup Exec forum:

"...
a small fraction of our media is FULL at less than the 'advertised' 400Gb native & in some instances only ~200Gb to fill the tape. Whereas we also have some at >1Tb reported!

The amount of compression achieved will ultimately depend upon the type of data - some types of data compress much more readily than others & in some instances the size can increase.

"...
The most common cause for poor data compression is that the data is simply not of the type that contains the redundancy required to allow the techniques used to reduce the size required for storage. Since it is the industry standard to quote the capacity of tape drives assuming an average 2:1 data compression ratio, this is around the level most customers experience and hence is pertinent to the performance of the product, this can lead to some customer dissatisfaction. This typically affects data types that use efficient techniques to minimize the data sizes they use initially (examples are MP3 files or JPG files) and the only solution is to accept that the data cannot be compressed and use the required amount of media to store the data required.
..."

http://h20000.www2.hp.com/bizsupport/TechSupport/D...

..."

Actual post: https://www-secure.symantec.com/connect/forums/there-1tb-backup-tape-limit-lto5-backup-exec

Hope this helps, but if not could you clarify?

Zahid_Haseeb
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Thanks Andy for your kind reply. Would you give some comments on the below.

1.) the below picture shows 21534003 of size but at some places in Netbackup it says some other figures(as above in snaps and also in available_media). My question is why Netbackup is showing different size of data at different places in Netbackup.

Andy_Welburn
Level 6

that explained the reason why some reports showed different figures to others - something to do with exactly where in the d/b NetBackup is getting it's information from & how it's reading headers etc etc. Had a look for this T/N when I first looked at your post this morning, but can't for the life of me find it at the moment! Will keep looking (& will probably come across it when I'm looking for something else!)

Marianne
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Zahid, have another look at your 'Tape List' report:

There are 24 Images on tape, of which  23 are Valid images. These 24 images are totalling 36200115.

Any other report will simply report on the 23 Valid images. You will best know why there is a difference between number of images and valid images (could be a failed backup in the middle of a multiplexed backup or an image that you have expired).

Fact is, you have one INVALID image that is occupying space on the tape. As you know by now, backups to tape are written sequencially. No backup application can reclaim/overwrite invalid/expired data in the middle of a tape.

Media marked as FULL means that 'End of Media' was reached while a backup was written. This is not a NetBackup 'decision', it is a physical state encountered by the hardware. You will be able to see this in bptm log.

Zahid_Haseeb
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(apart from this post i tried to compress a data folder with winzip and also took a backup via  Netbackup with compression in storage unit. The images which Netbackup made in the Storage Unit are not as small as winzip zip folder size)

Zahid_Haseeb
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is there any possibility to see the invalid image in Netbackup (like in Netbackup Catalog)?

Marianne
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Zahid, I don't understand what value you will get from an exercise like that - it seems that you are keeping a close eye on your backups - there was either a failed backup (will still be visible in Activity Monitor if within the last 3 days or Backup Status report if within last 28 days) or an image was manually expired (evidence should be present in admin log or bpdbm log).

You could possibly run a 'Tape Contents' report, but (IMHO) nothing will be gained from such an exercise...

Zahid_Haseeb
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Thanks Andy and Marianne. Marianne i am marking your post AS SOLUTION