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How to enable duplication jobs running on single tape drive

Pinku
Level 5

Hi Everyone,

My duplication jobs run one single tape drive each.

So each job keeps one tape drive busy till it gets completed. Is it possible that I make multiple duplication jobs running on single tape drive.

master server - solaris10, NBU - 6.5.6

media server - solaris10, NBU - 6.5.6 (2 tape drives)

1 ACCEPTED SOLUTION

Accepted Solutions

Mark_Solutions
Level 6
Partner Accredited Certified

Two ways around this - one of which has already been covered ....

1. Copy the current tape storage unit to a new one and set it to only have 1 drive and then set the DSSU schedule to use the new tape storage unit

2. Set the value of the STAGING_JOB_KB_LIMIT to 2147483647 ( and / or MAX_STAGING_JOBS to 1 which i think is still valid these days)

You wont get around the jobs per retention and they will have to queue, unless you allow multiple retentions per media (Not reccomended)

Hope this helps

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16 REPLIES 16

Marianne
Level 6
Partner    VIP    Accredited Certified

What are you using to kick off duplication?
Vault?
SLP?
Manually with bpduplicate?

How were your backups written - MPX or non-MPX?
Duplication job - keep MPX or not?

Only if original jobs were MPX'ed and duplication job is configured to keep MPX can multiple jobs be duplicated simultaneously.
 

Pinku
Level 5

Seems, I failed to have you understand the situation,

Its a basic disk, where backups are written first and then staging(from disk to tape) happens.

Backups are written MPX.

Marianne
Level 6
Partner    VIP    Accredited Certified

Sorry for the misunderstanding - you only mentioned 2 tapes (no disk), so I thought you were doing tape-tape duplication.

Disk staging relocation behaviour is described in this TN: http://www.symantec.com/docs/TECH44719

The default behavior in NetBackup is for a DSSU relocation job to first divide its list of images to be duplicated into separate groups for each retention level represented in the list.  Each of these retention groups is separated into individual batches that do not exceed 25 gigabytes of data per batch. Next, a bpduplicate command is executed to handle each batch of images.  If enough drive resources are available, all of these duplication jobs will immediately activate.  Otherwise, there will be a mix of active and queued duplication jobs based on drive availability.

It also describes how behaviour can be changed along with some examples.

A good understanding of the disk jobs is needed - amount of jobs, retention levels, job size...

Pinku
Level 5

That is again best practices and tuning for disk staging jobs.

And accoding to this note..images are divided into batches which do not exceed 25GB and each job will write on one drive only. And all other jobs will be in queue till the active jobs are completed.

Still, I haven't found resolution to my problem. I need how can I make multiple jobs going to one drive.

Marianne
Level 6
Partner    VIP    Accredited Certified

Have you enabled multiplexing in STU properties?

StefanosM
Level 6
Partner    VIP    Accredited Certified
If you need to use ony one drive for duplications and have the other one free for backups and restores you can use the folowing. copy the storage unit to another name and limit the drive number to one. use the new storage unit as destination of the duplication jobs. stefanos

Pinku
Level 5

Marianne
Level 6
Partner    VIP    Accredited Certified

If you look in Job details for the Queued jobs - what is the reason for it being queued?

StefanosM
Level 6
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Duplications from disk storage unit can not be multiplexed to tape.
Only tape to tape duplications can retain the backup multiplexing.

 If you have 4 drives, then you will get 4 active duplication jobs from disk to tapes, one per drive, no mater what max streams per drive you have.

Pinku
Level 5

@Stefanos Monovasios - So there is no way out?

I had already checked that, the media multiplexing setting on staging schedule is disabled.

StefanosM
Level 6
Partner    VIP    Accredited Certified

if you need to have more active duplication , no there is no way to do it.   Unless you buy more drives :)

If you need to have one free drive, use the tip I gave you.  

Pinku
Level 5

how it will keep one drive free?

i mean if the original storage unit has 4 tape drives and max write drives configured as 4
 
then the copied storage unit where max write drives configured as 1
 
I don't think 1 drive will be free unless i decrease the max write drives to 3 on origibal storage unit settings?

Marianne
Level 6
Partner    VIP    Accredited Certified

Please tell us how many images are included in each job.
If I remember correctly, this will be listed in the Job Overview.

If we look at the TN mentioned above, a whole 'bunch' (batch) of images will be included in each duplication job:

The default behavior in NetBackup is for a DSSU relocation job to first divide its list of images to be duplicated into separate groups for each retention level represented in the list.
Each of these retention groups is separated into individual batches that do not exceed 25 gigabytes of data per batch. Next, a bpduplicate command is executed to handle each batch of images.

StefanosM
Level 6
Partner    VIP    Accredited Certified

you have it.

If you put  max write drives = 1 then only one drive will work.

If you put  max write drives = 3 then three drive will work and one will be free for restore jobs. (and backups, if you use the other STU)

Pinku
Level 5

Image count is different in each job, as the bunch is created on the basis of retention period. Same retention period images will be combined into bunches and then converted to groups of size 25GB or more.

Mark_Solutions
Level 6
Partner Accredited Certified

Two ways around this - one of which has already been covered ....

1. Copy the current tape storage unit to a new one and set it to only have 1 drive and then set the DSSU schedule to use the new tape storage unit

2. Set the value of the STAGING_JOB_KB_LIMIT to 2147483647 ( and / or MAX_STAGING_JOBS to 1 which i think is still valid these days)

You wont get around the jobs per retention and they will have to queue, unless you allow multiple retentions per media (Not reccomended)

Hope this helps