Need script

[nanochan]

hi, any idea where i could get this "script" ?

(Reference: https://www-secure.symantec.com/connect/forums/symantec-netbackup-keeps-using-same-tapemedia-write )

seems to me that even when i set a 2weeks retention period my backup still continues to append into the same tape despite settings set to:

1. non compression

2. my data consists of 700GB of data

3. LTO-4 at 800GB

4. even at full or differential

5. on top of that my differential on the same tape backup same amount of data as my Full backup (no idea what went wrong)

any reason?

thanks.

[Yogesh9881]

Where i could get this "script" ?  ---  Which script you are talking about?

what master server  OS version  ?  NBU version ?

[RiaanBadenhorst]

Have you read this? What you're describing as an issue is actually regular operation for netbackup.

http://www.symantec.com/docs/HOWTO33982

As for writing Full and Diff/Incr on the same tape. You probably have this setting set

"Allow multiple retentions per media" in the host properties of the master > media properties

[Mark_Solutions]

nanochan

As i said in your other post you need to be aware of the following:

1. Once NetBackup writes to a tape it will keep using it until it is full

2. The drive hardware uses compression by default so an LTO4 tape can hold up to 1.6 TB at a 2:1 compression ratio

3. If the retentio period of Full, Incremental and Differential backups are all the same then they will all go to the same tape.

4. If you allow multiple retentions per media in the Master / Media Server host properties then all backups will go to the same tape regarless of their retention period.

5. If you need to split Full and Differential backup onto different tapes then either:

a) Do not allow Multiple Retentions Per Media and set the schedules of the Full and Diff / Inc to have different retention periods

b) Put the tapes for Full backups in one pool and the tapes for diff / inc in another pool and then set the Policiy attributes to use the Full pool and then in the Diff / Inc schedule override this pool to use the Diff pool.

Hope this helps

[Mark_Solutions]

nanochan

Are you happy with the advice given?

Is so please close the thread (mark a solution), if not then please give us an update

Thanks

[nanochan]

compression is set to off - so i believe tape can only collect up to 800GB of data.

allow multiple retention is set to off as well.

still the same exact issue.

[mph999]

I presume you mean compression in NBU is off.

The drive will still use hardware compression, this will be why you can fit >800GB on.

The hardware compression is happening bacause of the device file you are using, for example, on Unix:

/dev/rmt/0cbn = hardware compression (that is what the 'c' is)

Martin

[Mark_Solutions]

nanochan

You say compression is set to off - if you mean in the Policy then this has nothing to do with the tape drive, it is just whether NetBackup compressed the data as it is backed up.

The compression is done at the drive hardware level and is actually pretty tough to turn off so i would be very surprised if you have managed to turn off tape drive compression, in which case you should be able to stire up to 1.6TB per tape.

Hope this helps

[nanochan]

thanks for replying,

i am on Windows 2K8 though.

so the tape will definitely be compressed automatically is that what you are saying ?

strange design

okay...

if i set 2 policy with both having different pool but frequency as daily schedule

eg. Full backup, frequency 4 weeks (Sun), Differential backup, frequency 1 day (Mon - Sat), 8pm to start writing

pool 1 - effective date: 23/10/2011, time 1am (Tape 01)

pool 2 - effective date: 30/10/2011, time 1am (Tape 02)

which pool will netbackup picks on 30/10/2011 & 31/10/2011 or will simply write on both ?

[Marianne]

The pool is specified in the policy. NBU does not mix retention by default.

Policy 1 will still go to pool 1, but will choose a different tape in pool 1 for different retention.

Policy 2 will still go to pool 2, but will choose a different tape in pool 2 for different retention.

Please see if these two explanations help:

About selecting media in robots on Windows 
http://www.symantec.com/docs/HOWTO33982

and

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

Please read the explanation as well as Andy's comment on why Multiple retentions on a tape is NOT a good idea.

[Mark_Solutions]

As I said previously the tape drive hardware is designed to compress data as much as possible to get the maximum possible on each tape - it is nothing to do with Netbackup or the operating system Hope this clears that up

[Mark_Solutions]

Hi Are you happy with the info on here or is this still outstanding, as the thread.is still open / unsolved Thanks