Michael Berkowitz wrote:
>
> Attention disc performance mavens:
>
> We are probably going to replace our HP-FL disc arrays with IBM SSA
> drives in the near future.  This of course is a topic in itself.  Our problem
> is what to do about device 1.  We do not want it to be anything but a fully
> supported HP drive, so what should we do.  Should we keep our present
> C2252HA (2.72 GB HP-FL) disc array, or go to the A3540 Model 10 disc
> array with the minimum 3 disc modules (12.6 GB, 4GB usable for dev 1).
> Which would be the faster disc, the more reliable disc, and the easiest to
> recover if a disc module goes down?  Which has more redundancies?

Mike,

JOTTOMH, in your situation I would go with the 4 GB A3540 array for ldev
1. The reason has less to do with performance (which I can't speak to
because I'm not that kind of maven) than the fact that if you are
restricting your MPEXL_SYSTEM_VOLUME_SET to one drive (which you are
effectively doing, if I read you right), why not have as much usable
space as you can on your boot/system drive? (And 4 GB is, AFAIK, all you
can use on ldev 1 -- unless HP removed that restriction when I wasn't
looking...)

BTW, if I'm misreading you, and you can combine some SSA drives with
ldev 1 to create a system volume set, forgive me; I'm not familiar with
the capabilites of SSA.

Having said that, on our 995 we have three drives (ldev 1 = C2259HA and
two other ldevs = C2254HA) making up the system volume set, which gives
us a little breathing room for the SYS account and some additional stuff
we have on the system volume set, but still leaves enough room on ldev 1
for those things which *must* go there for the system to boot. They have
been very reliable drives <knock-wood>, no failures in over three years.
I have not always been pleased with the i/o performance (sometimes have
read waits > 2 seconds), but I suspect we just need to add more drives
to our system volume set to reduce the bottlenecks.

FWIW, YMMV, HTH, etc.
Patrick "more of an English Language maven" Santucci
--
Patrick Santucci
Technical Services Systems Programmer
KVI, a division of Seabury & Smith
Visit our site! http://www.kvi-ins.com
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