The tape were not expiring...

[mrinal_sarkar62]

Hi,

We have NBU 6.5 over HP Unix 11.5 and a Robotic tape librery.

We have a polciy that takes backup of  flat files generated by an application( from the scanned image by the user.).

There were seven policy for seven day and all seven different policy takes full backup. These all seven policy have seven different volume pool with single tape in each pool.

The retantion for all policy were 1 week.

Data size - 500GB (Apprx.)

Tape is LTO4 (800/1600 GB size)

The problem;-

After  one week the backup were failing with error status 96. Checking the details, it showed that the backup started writting some GB (Approx. 300 GB) data then it is looking for another tape and fails to get one (as there is one tape in that volume pool) tha backup were failing with status 96.

As if the tape is full and it is looking for another tape.

Where the tape is used for the first time after the retaintion period.

I have manually expired the tape and the backup was successful.

There is another policy of the same server is being used to take backup on that same tape volume(Sheduled next to this backup), which in turn also fails.

Is the tape not expiring as it should be or is there any thing else need to be done.

OR

I need to expire the tape every time it is full.

Please, help.

Thanks.

[spulipati]

Check if the below file exists on the master server. If it is there then thats the culprit.

/usr/openv/netbackup/bin/NOexpire

Thanks

Sandeep

[J_H_Is_gone]

Lets say that you have a tape that was first written to last night at 6 pm on the 14th (Monday)

but the job did not finish writing to the tape until 2 am on the 15th.

and you have a 2 week retention.

That means the tape is not going to expire until 2 am on the 29th.

Where it seems you expect to be able to use it again on the 28th (Monday), but it has not expired yet.

So at 6 pm on the 29th it writes to the tape, but is appending to the end of the tape because the 14th's backup has not yet expired.  So now 2 weeks from now you try to backup to the same tape again on Monday, but the backup for the 29th has not yet expired, so the new backup again appends to the end of the tape. 

so you end up with a tape that has 2 expired images on it and 1 good one that still has 2 week retention.

It will continue in this way until the tape is FULL. (By FULL I mean that the backups have appended to the tape until it has reached the End Of Tape)  Once full the backup will ask for another tape, if no tape is avail it will fail with a 96.

The easiest way to see if a tape is expire is look in the GUI under media.  It will show you the first time it wrote to the tape when it had no valid images on it (that would have been the 14th in my example) it will also show you when the image with the longest retention on the tape will expire.  The tape will not be a "scratch" until after that time(but it could be up to 12 hours after that time before netbackup gets around to actually scratching the tapes.

It appears that you are trying to micro mange your tapes with separate daily policies and volume pools which is only going to give you headaches like these.   By practice if I had a tape written to on Monday night with a 2 week retention, I do not put it back into the library until Tuesday.

If you had 1 volume pool with extra tapes, or 1 pool plus a scratch pool, each daily backup would get a tape from scratch pool and use it,  you take it out and send offsite. Bring it back the day after the retention when it is a scratch again and put back into the library.  Have a few more tapes in the scratch pool because you have to wait that extra day.

I have a blog that explains how Netbackup writes to tapes and how expiring images affects the tape.

http://www-secure.symantec.com/connect/blogs/understanding-how-netbackup-writes-tape

[mrinal_sarkar62]

Hi,

In our situation , all policy take backup on all 7 days and it have retantion period of one week.

I guess, the image clean up might not getting enough time to remove the expire image in all the tapes.(As per the KB article, all images after the retantion period , NBU takes12 hours to expire the image by cleaning the tape)

As of now I have changed the retantion periond and custamized it , changed to 6 days.

So, that alll the images will have enough time to expire them, after the retantion period , (i.e. one full day).

Lets hope for the better.

Thanks.