Lloyd,

We tried going direct-to-tape with our LTO.  That worked OK on Domino and
Oracle, but it was terrible on file servers.

What I finally did was put a fairly small (24 GB) disk pool upstream and
set a MaxSize on it (50 MB).  That allows small files to collect on disk;
we force migrate to tape at 5:00 pm to get ready for the next backup
window.

If you just want to get the data on tape quickly, you might set a low
migration point, like 10%.  We use that on the disk pools upstream of our
3575s.  Each has a 4 GB disk pool with migration set at 10%, so as soon as
it accumulates 400 MB of data, migrations launch.

That fixed the problem completely.

Tab Trepagnier
TSM Administrator
Laitram LLC








Lloyd Dieter <dieter AT SNRGY DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
06/13/2003 09:56 AM
Please respond to "ADSM: Dist Stor Manager"


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


Are you seeing this behavior for backups/restores, or just tape-tape
operations?

If you are getting this for backups/restore, try using a disk storage
pool, if you are not already doing so.  The key to success with LTO1
drives is keeping their buffers full and the drive in streaming mode; if
you are trying to do directly to tape, you may not be able to "feed" them
fast enough to keep them streaming.  Once they start working start/stop,
performance just falls apart.

If you are seeing poor performance tape-tape (reclamation, copy pool
backups) and are using a disk pool, try flushing the disk pool out to tape
before you begin the tape-tape operation.  I think you'll see a
significant performance gain.

-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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