What kind of LAN?

You must match the speed you can read the date from the source disk drives,
the speed
the data can be sent across the lan,  and the write speed of the tape
drives.

We run  LTO I drives to backup our SAP systems.  We use SAn attached disk
and SAN
attached LTO drives.  We are able to spin 4 LTO I drives  at 30MB/s (total
of 120MB/s throughput) .
We use drive compression and get about a 4-to-1 compression ratio (+400GB
per tape).  Note,
we use HP Omniback for this, not TSM.

How much data can you push from the source system to the TSM server via the
LAN?  If it's a
10/100 ethernet, then you won't even get 1 LTO drives worth of speed
(10MB/s).  If the LAN is
GE, then you might be able to get 2 LTO drives spinning (60MB/s).  I
suppose it's
possible to get 3 spinning (90MB/s), but I've never seen a GE connection
run that fast sending
real data.   I don't see how you expect to keep 4 drives spinning.

If you can get the drives spinning at full speed, then you probably should
only attach 2 drives per
FC adapter.

The worse thing you can do is run lots of drives but starve them for data.






                      Juan Jose Reale
                      <[email protected]        To:       ADSM-L AT VM.MARIST 
DOT EDU
                      OM>                      cc:       (bcc: Richard L. 
Rhodes/OE/FirstEnergy)
                      Sent by: "ADSM:          Subject:  HBA's for backup SAP ?
                      Dist Stor
                      Manager"
                      <[email protected]
                      .EDU>


                      09/18/2003 05:55
                      PM
                      Please respond to
                      "ADSM: Dist Stor
                      Manager"






     Hi everybody!

        Some of you know how many HBA's (Fibre Channel Bus Adapter 1000
Gb/s) we should get for backup SAP via LAN.  We have four drives LTO I
(3584) and are running TSM 4.2.2.10 on AIX and TSM Client on Window 2000.
We are not using SAN.

        Big thank.  I very much look forward to hearing from you.
        Regards.
        Juan R.
        System Administrator.

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