RE: system p announcement

from: "Joe Pluta"
Not that you would specifically know, Walden, but this seems like a good
place to ask one of my uber-newbie questions. Since IBM storage works on
single-level store and other systems don't, does it work and play well
with other on a SAN?

I know virtually nothing about SANs, so I don't know how you allocate

chunks

of storage to a specific server, nor how the SAN converts the internal
addressing scheme of the server to the SAN location. I'm still a little
fuzzy on how these things work together; can you put, for example, System

i

storage and Windows storage in the same recovery set on the SAN? If not,

if

the System i storage is an isolated set of disks, then what's the

advantage

of the SAN?

Really, just asking. I'm clueless in this area. I've never needed a SAN

in

my own operations, although I suppose a NAS device is my first step in

that

direction.

Joe, In my previous job I did a i520 with no internal drives, boot from SAN
a little over a year ago. I would not do SAN attached storage on a i5 system
w/o being at V5R3 or above. The OS levels below 5.3 did not offer multi-path
support. Multi-path provides more than one path to the SAN drives, which
allows you to have redundancy and fail-over capabilities. It worked very
well. In i5 land you can only run 32 LUNS per Host Bus Adapter (HBA), so for
multi-path to work I only configured 16 LUNS per HBA. That way if an HBA
fails and you have setup your zones correctly the other HBA will run all 32
LUNS until the failed part is replaced.

IBM recomds that you isolate workloads on the SAN. For instance only Windoz
work on an array of drives, pSeries work on another set of drives, and
iiSeries work on another. We had all three environments on our SAN w/o any
issues. Our San was an IBM 2105-800 (the Shark). I am lookin at implementing
a SAN here. An IBM DS4700, I know I can't do my iSeries on it, but I don't
have the $$$ for the DS6800, maybe next year.

Once you experience the SAN life you'll never want to do staorgae the old
way again, at least I didn't.

Bob Schwartz
Director of Technology Services
Glynn County School System