Lloyd,

after requested clarifications is was revealed that the adapter is 2940UW
(40 MB/s) with the drive alone on the bus. Thus the bus might be a
bottleneck only is case compression ratio goes far beyond 2:1.
Colby, you can have this in mind - 40:15 ~= 2.5:1. After that point
uncompressed data could be limited at the SCSI bus, compressed data will
come at rate less than 15 MB/s and drive will start shoe-shining. For
compressions lower than 2.5:1 everything ought to be fine.

Zlatko Krastev
IT Consultant






Lloyd Dieter <dieter AT SNRGY DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
13.06.2003 17:57
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Re: TSM LTO 3580 Performance


Also...an Adaptec 2940 is an older SCSI-2 card...10MB/sec, isn't it?

Maybe that's an issue....

-Lloyd


On Thu, 12 Jun 2003 08:11:51 -0500
Colby Morgan <cmorgan AT DATA-TRONICS DOT COM> wrote:

> We in the process of moving to an IBM 3580 external LTO drive for manual
> offsite vaulting of primary storage pools.  I have read several older
> reports on http://msgs.adsm.org about poor performance with TSM, LTO and
> small files.  We are experiencing the same behavior and I was just
> curious if anybody has ran into this lately.  We see about 10-15GB/hour
> with small files and 42-57GB/hour on larger files.
>
> We are running TSM 5.1.6.5 on Win2k SP3.  The drive is an external IBM
> 3580 and is the only device hooked to an Adaptec 2940 SCSI controller.
> We are also running v5.0.5.4 of the IBM 3580 drivers.
>
> I maxed out the following server options (which helped):
> MoveBatchSize     1000
> TxnGroupMax             256
>
> I also set the drive parameters via ntutil as described in this Redbook
> (which also helped):
> http://www.redbooks.ibm.com/redpieces/pdfs/sg246268.pdf
>
> Anybody else ran into these problems?
>
>
> Thanks,
>
> Colby
>


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