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Backup to Disk To Tape

Level 4

Hi, we are running NetBackup 7.7.3. 

We are currently backing up specific servers to disk, so that the backup is faster, and then sending it to tape. But we are getting errors from time to time where we do not have enough space available on the disk. Looks like the disk is not getting copied to tape or that it's not getting erased.

Is there a way to have the backup to was made on disk to be sent to tape as soon as it's done?


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Can you check NetBackup Administrator's Guide,Volume I. If you want only sent backup made on disk to as soon as its done, you can you Storage Lifecylce Policies ( SLP).

If you want to only erase the disk after backup to dis was done, I belive that you can create a Vault. Take a look this document.




Level 6
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What type of Disk Storage Unit have you configured? Can we assume Basic Disk?

With Basic Disk, you cannot use SLPs. You can only create staging schedule(s) to run duplications a number of times per day (every xx hours). Disk space will only be cleaned up if images have been successfully duplicated and high water mark is reached.

Can you tell us what high and low water marks you have specified in STU config?

Best to provide sufficient space to hold at least 2 full backups on disk.

If you have configured Advanced Disk or MSDP, then please let us know.

Hi Marianne,

You are correct, we are using Basic Disk. We have a staging schedule configured, I guess incorrectly. The High water mark is set to 50% and low water mark to 10% right now.

There's the issue, we are not able to give enough space to hold 2 full backups, only 1. That's why I want to send the data to tape as soon as possible when the backup to disk is complete.

What would be the best configuration with Basic Disk?


I will take a look at the Admin guide also, thanks.

*Deplicate reply was deleted*



Level 6
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Think about your config - you don't have big enough storage, and then you config HWM as 50%?
The other 50% cannot be used and is therefore wasted.

The default is 98%.
Why not stick with that?

Well, looks like I didn't understand the High/low water mark correctly. I thought that by setting it to 50% it would start to copy to tape when it was full at 50%.

Guess I need to read the manual.  :)


Thanks for the suggestion Marianne, I'll give 98% a try.


IMHO - you should ponder on the rate you write data to the disks as well as the rate to empty it out, since it does not start cleaning until it hits the high water mark - if you have a smller size disk, or a lot of backups at once, you may want 90% instead. 

I have had high water mark set and load flow right past it and fill the disk due to lag in starting the cleanup and purge.

NetBackup on Solaris 11, writing to Data Domain 9800
duplicating via SLP to LTO5 & LTO8 in SL8500 via ACSLS

Is there a way to schedule the copy to tape?

I have a  large backup that goes to that disk, around 10 jobs running at the same time. We are doing this because it's faster to send to disk and we don't have to wait for tapes to be available.

When it's done I would like to send it to tape. If I set the High water mark to 98% the disk will get full when the next backup runs and it won't have time to get to tapes, well I'm pretty sure it won't. And if I set the high water mark too low the backup will fail as it will run out of space.

Level 6
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Is there a way to schedule the copy to tape?

Yes. Exctract from Admin Guide I:

Staging schedule option in Change Storage Units dialog
Click the Staging Schedule option to configure the relocation schedule for this
storage unit. A schedule is what makes the disk storage unit a basic disk staging
storage unit. During the relocation schedule, the backup image is duplicated from
the temporary staging area to the final destination storage unit.
See “Disk Staging Schedule dialog box” on page 587.
See “Enable temporary staging area storage unit setting” on page 576.
See “About basic disk staging” on page 579.
See “About staging backups” on page 578.

The schedule looks the same as a policy schedule.
You can config this schedule for every 3-4 hours or maybe even every 1 hour to look for completed disk backups that can be duplicated to tape.

If one backup is going to fill up the DSU, then you need to motivate for more storage.
As I've said before - staging/duplication can only be done after completion of backups.
There is no point in battling with insufficient disk space.
You will be better off backing up directly to tape. Make use of multiplexing and multistreaming for optimum performance. 

Two useful DSSU TNs:

DOCUMENTATION: Description of NetBackup Disk Staging Relocation Behavior

Disk Staging Storage Unit (DSSU) cleanup behavior

Hi Marianne,

Thanks for all the info, I should be able to get it working now.