Does anyone have a good (or even fair) way to manage tape drive attachment
over a SAN?

The problem is that TSM (3.7.3.8, the latest version supported by the
software used on the project) attaches to tape drives through OS "special
files" (e.g. rmt0).  In my case, AIX directs these to each path to a WWN
on the SAN.   This results in many rmt's , in my case six: two for each
tape drive (3590-E1A fibre drive has two ports) times the number of fibre
cards in the host (in my case three).

The consequence is that I have 11 tape drives showing up as 66 rmt's!!
These must be selectively configured into TSM so as to load balance over
the fibre and minimize the waits for drive access (TSM waits a
predetermined amount of time for the drive if it is busy, such as if it is
using the drive's other port).

To further complicate matters,  when a tape drive is replaced, it comes in
as a new WWN and the old WWN disappears.

Two fixes for this come to mind:
1) Tivoli could re-write the drive definitions to allow attachment to a
WWN and handle the multiple paths internally;
2) IBM could extend SDD/DPO to tape.

For now I am doing the bookkeeping, remaining vigilant, and praying for
real SAN compatible TSM.

Orville L. Lantto
Datatrend Technologies, Inc.
121 Cheshire Lane #700
Minnetonka, MN 55305
V: 952-931-1203
F:952-931-1293