NetBackup doesn't handle multiple disk storage or disk-staging storage
units very well.  I think you'll need to set the full storage unit
to be "on demand only" to avoid NetBackup directing  backups to it.

I started out with 3 1TB disk storage units, testing both disk-staging
and regular disk storage units.  I backup about 2TB daily.  I played
around with directing certain types/sizes of backups to specific
storage units.  Nothing worked for me.

Next, I tried striping the disks to make one large storage unit.
I found that I could get "fair" backup writing speeds with 10 concurrent
backups, but if I attempted to stage diskimages to tape while backups
were written to the disk, then the disk write speed dropped dramatically
and the disk read speeds dropped to 200KB/sec.  So my storage unit
still filled up faster than I could empty it.

My current configuration is 1 master server with 2 7TB storage arrays
and a 3-drive LTO2 library.  Each storage array is an on-demand-only
storage unit.  Every day, I have a script which sets all of my backup policies
to use the empty storage array while I stage the diskimages to tape from
the full storage array.  My CPU is pegged during backup windows because
the disk writes for each backup (bpdm) takes up about 1.3% of the cpu
and I'm running 24 concurrent backups.  Disk write speeds during peak
backup windows fluctuate between 2000KB/sec and 9000KB/sec; disk reads
from the non-backup storage unit during peak backup windows are
1500-4000KB/sec.

Wish I had better news for you.

--kathy

> Subject: RE: [Veritas-bu] [DC 3.4.1] disk storage units
> Date: Fri, 5 Aug 2005 12:56:15 -0600
> From: "Jorgensen, Bill" <Bill_Jorgensen AT csgsystems DOT com>
> To: "Arne Kloecker" <arne AT topnet DOT de>, <veritas-bu AT 
> mailman.eng.auburn DOT edu>
>
> Arne:
>
> No. I am not aware of anything you can do except write scripts to
> interact with NBU.
>
> Bill
>
> ----------------------------------
>    Bill Jorgensen
>    CSG Systems, Inc.
>    (w) 303.200.3282
>    (p) 303.947.9733
> ----------------------------------
>
> -----Original Message-----
> From: veritas-bu-admin AT mailman.eng.auburn DOT edu
> [mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of Arne
> Kloecker
> Sent: Thursday, July 28, 2005 5:50 AM
> To: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: [Veritas-bu] [DC 3.4.1] disk storage units
>
> Hi,
>
> i added some disk storage units. All of them are NOT "on demand only".
> The classes do not ask for a specific storage unit either.
>
> But when the first disk storage unit is full, the backups fail. They
> won't use the next disk storage unit (which is free).
>
> Does anyone know how i can make veritas use disk STUs just like tape
> STUs (in the way that if one is unavailable it trys the next).
>
> Thanks for any help.
>
> Best regards
>   Arne
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu
> http://mailman.eng.auburn.edu/mailman/listinfo/veritas-bu
>
>
> --__--__--
>