I haven't had any responses.  Any thoughts?

Is it possible to have 2 3590 device classes on the same ADSM server sharing
the same 3494 library and 3590 drives?  I want my larger clients to go
directly to a 3590 device class which uses the 3590 H/W compression.
However I want the smaller clients to use S/W compression and backup to SSA
disk,  this will then be migrated off to the non-compressed 3590 device
class.  ( so that the 3590 is not trying to compress already compressed
data).  Would this cause problems with mount points, since both device
classes will be sharing the same 3590 drives.

I do not have a test server, and I'm reluctant to try this out in
production.

Richard.


> -----Original Message-----
> From: Bates, Richard
> Sent: 01 October 1999 17:08
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      2 device classes sharing the same library
>
> Hi,
>
> 4 servers at ADSM 3.1.2.40 on AIX 4.1.5
>
> I currently have a 3494 with 12 x 3590's.  This is partitioned into 4
> libraries so each ADSM server has exclusive access to 3 x 3590.
>
> Currently I have the format on the device class set to 3590C, so the
> drives use built-in compression.  Some of my larger clients do not use S/W
> compression and backup directly to this device class.  We get great
> performance.  However some of the smaller clients use S/W compression and
> backup to SSA disk first. This is migrated to 3590 later on in the day.
> We do not get such great performance during the migrate.  Having read some
> of the comments about using both H/W and S/W compression I would like to
> change my setup.
>
> I would like to define another 3590 device class which does not use H/W
> compression.  The SSA disk stgpools would be migrated to new 3590 stgpools
> which use this new device class.  Hopefully we would get better
> performance during the migrate.
>
> Is it possible to define another 3590 device class which uses the same
> library and drives?  I would set the "mountlimit" to "drives" on both
> device classes.  If a drive is being used by one device class will the
> other device class know that it has one less mountpoint?
>
> Any ideas?
>
> Richard.
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