On Jun 16, 2009, at 11:43 PM, Steven Harris wrote:

One possibility would be to install TSM for SAN on the partitions
that need
it, but there is some administrative overhead with doing this, and
we are
finding that drive sharing is not as error free as we would like
with only
a 5 way split.  We are seeing drives getting hung up with reserves,
and are
afraid that this will get much worse if more AIX lpars share them.

Reserve problems make me wonder about storage agents that are not
using persistent binding (If \dev\rmt3 goes from being the third drive
in a frame to the second drive in a different frame, without the
library manager knowing, what ensues is NOT hilarity) or that are
especially poorly behaved (At one still-recent job, IBM analyzed
enough drive data from hung-drives to help us identify a problem
child, who promptly was put in the penalty box until he got a new HBA).

As Remco says, it doesn't have to be that way. I'm now on my third
shop with large numbers of servers and storage agents sharing one or
more libraries.