Ruud,

You CAN use ANY of the devices listed.  Notice (looking at the Gateway) that
your Medium Changer is listed on the first SCSI channel.  Be aware that the
communications path between TSM and your library is across THAT path.  Since
you only have one SAN Data Gateway (and I assume on FCA on your TSM server
associated with it), this shouldn't be too hard to troubleshoot in the event
of Fibre Channel errors.  The downside to your setup is that you'll have 4
LTO drives (and their library) going across ONE Fibre Channel path.  You
have a slight bottleneck there.  Three drives per path is better, with two
giving the best performance.   Two LTO drives can't fully use the entire
bandwidth of a FC path, but they'll come close occasionally if they have
fast access to your storage pools during disk-to-tape migration.

What surprises me is that you see all of your devices twice (once for each
SCSI connection to your Gateway).   I see each of my devices three times,
but I have three gateways (using 5 SCSI connections - one to each drive).  I
would have expected to see each of your devices only once (assuming your
drives are 'daisy-chained').

How are your drives connected to your SAN Data Gateway...?

Thank you,

Jeff Caffey
Enterprise Systems Programmer
(AIX & Storage Administrator)
Pier 1 imports, Inc.  -  Information Services
jlcaffey AT pier1 DOT com
Voice: (817) 252-6222
Fax:   (817) 252-7299

 -----Original Message-----
From:   Van Ruler, Ruud R SSI-ISES-31 [mailto:Ruud.R.vanRuler AT is.shell DOT 
com]
Sent:   Thursday, May 31, 2001 9:05 AM
To:     'ADSM: Dist Stor Manager'
Cc:     Caffey, Jeff L.
Subject:        RE: Response to multiple questions regarding LTO libraries
on a S AN.. .

Jeff

Equipment involved:
IBM 2108-G07 SAN Data Gateway (1)
IBM 2109-S16 SAN Switch (2)
IBM 3584 LTO Library (1 Library with 4 SCSI Drives)

Entering the "lsdev -Cc tape" command within AIX produces this output:
rmt0 Available 14-08-01-1,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt1 Available 14-08-01-2,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt2 Available 14-08-01-3,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt3 Available 14-08-01-0,0 IBM 3580 Ultrium Tape Drive (FCP)
smc0 Available 14-08-01-0,1 IBM 3584 Library Medium Changer (FCP)
rmt4 Available 14-08-01-1,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt5 Available 14-08-01-2,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt6 Available 14-08-01-3,0 IBM 3580 Ultrium Tape Drive (FCP)
rmt7 Available 14-08-01-0,0 IBM 3580 Ultrium Tape Drive (FCP)
smc1 Available 14-08-01-0,1 IBM 3584 Library Medium Changer (FCP

Looking at the Gateway:
SCSI channel - 1
        Tape Device[0:0] - 8
        Medium Changer [0:1] - 9
SCSI channel - 2
        Tape Device [1:0] - 2
SCSI channel - 3
        Tape Device [2:0] - 4
SCSI channel - 4
        Tape Device [3:0] - 6

Which devices can/should I use ???
What is the relation between the Gateway (eg. Tape Device [0:0] - 8) and the
output of the "lsdev -Cc tape" command ???

thanks in advance


Ruud van Ruler,  Shell Services International BV - ISES/31
Our Central Data Storage Management home page:
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Email Internet: ruud.r.vanruler AT is.shell DOT com
                          rvanruler AT hotmail DOT com

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