We have our primary pool on SATA (IBM DS4100) arrays which are behind an
IBM SVC and we have not seen any performance issues.  There was initial
concern with performance and reliability of the SATA drives, but with
the SVC in the middle, neither have been an issue.

Mahesh

>>> Wanda.Prather AT JHUAPL DOT EDU 6/21/2006 12:06:22 PM >>>
OK, I'll chime in too.

I think Content Manager is an excellent SATA application - VERY SELDOM
USED data should be happy there.

For a primary disk pool, it can work in some environments, but can
also
be a BAD idea.

Thing is, even all SATA is not created equal. Before you decide you
can
put PRIMARY disk on SATA, ask about SUSTAINED throughput rates.

If your data needs to go SOMEWHERE ELSE (like get copied or migrated
to
tape) from the SATA disk, think carefully. If you're talking a LOT of
data, think VERY carefully.

I've worked with some SATA disk that drop to as low as 8MB/second
after
you exceed the cache read ahead/flush capacity (and that's on READ
I/O,
not even writes!).

So now let's think: Reading at 8MB/sec, writing to LTO3 that runs (or
tries to) at 70MB/sec - can you say "BOAT ANCHOR?".

Wanda
"There is no such thing as fast, cheap, reliable disk." - don't
remember
who said it, but I agree
"Shopping for the cheapest disk makes no more sense than shopping for
the cheapest brain surgeon." - me







-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf
Of
Allen S. Rout
Sent: Wednesday, June 21, 2006 11:29 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: TSM diskpool on SATA

>> On Tue, 20 Jun 2006 15:06:17 -0500, Mark Stapleton
< mark.stapleton AT USBANK DOT COM > said:

> I would *never* use a SATA pool for a primary TSM storage pool.

Allen the Pedant simply has to chime in on this.

I'm actually contemplating a SATA pool for a large chunk of "primary"
storage right now. However, this primary data is online/nearline
storage for a Content Manager installation. It is used as a
document-management system to make some of our offices less paperful;
the access patterns for this make a very good fit.

Another primary stgpool we're considering sticking on SATA is the
Space Managed data. It's a great way to consolidate large,
seldom-used filespaces, and again the access patterns fit very
nicely.

Now, I don't think I'm actually disagreeing with Mark in these cases,
but my antennae quiver whenever we approach a philosophical asymptote.


- Allen S. Rout
- I could *never* keep my mouth shut. ;)