>From IBM's 3590 web site:

>The new AIX(R) high-availability failover mechanism in the AIX tape
>device driver enables multiple redundant paths in a Storage Area
>Network (SAN) to 3590 Model E and Model H Tape Drives having Fibre
>Channel attachment.

and

>The AIX tape device driver also offers dynamic load balancing for
>3590 Fibre Channel drives used in an AIX SAN environment.

We will soon be upgrading our current TSM server with scsi attached
3590E drives to FC attached 3590H drives.  I've been trying to find
out more information on just what this path failover and load
balancing is, and, how it works - but not finding much.

Setup:  We will have 14 drives and 2 FC switches - each drive
attached to both switches.  From the aix system (aix5.1) we will have
3 fc connections to each switch (6 total).

q1)  What will the rmt devices look like?  How many will there be?

Will I have one rmt device for each HBA/drive?  If the tape drives
were disk luns and there was no zoning, I would expect 84 aix devices
(6 hba's times 14 devices - each tape drives showing up 6 times).

q2)  In this environment, what is the "primary" path and what is the
"failover" path.  How is the primary picked?

q3)  Does load balancing use all paths?

In other words, will only 3 of the HBA's be use while the other 3 sit
idle unless a switch failure occure?  Are all 6 paths to to any
particular tape drive usable if the system decides to use them?

q4)  Is all this a function of AIX, the atape driver, or both?

q5)  Is there any documents that describe this more, like a redbook
or tsm manual . . . .I didn't find much.

Thanks

Richard Rhodes
rhodesr AT firstenergycorp DOT com