Pre-SUMMARY: IBM SAN, HBA, Multipathing & Volume Mgmt

From: Jeff Germain <>
Date: Thu Jul 15 2004 - 15:04:04 EDT
Well, I only got four replies to this one (not counting the
replies-that-shall-not-be-named, and one cold call who got hung up on).

The replies conflicted enough to make me realize what I guess I already
knew -- you have to try all the different combos out yourself and decide
which is better for you.

Here are some of the comments:

o) "For more than 2 paths (if you want to use them all active/active) then
DMP is not a good solution. In fact it's causing me HUGE issues on one of my
SANs"  [Submitter's NOTE: we have 4 physical paths to each LUN]

o) "Don't even consider SDD.  IBM basically knows nothing about Sun and
their recommendation to us was to go with Veritas DMP."

o) "I don't know anyone using IBM's SDD and Sun's SSTM isnt designed to work
with a Shark.  I would definitly go with DMP.. It works great"

So, don't use DMP, SDD, or STMS.  :-(  Hmmm... back to the old drawing

What we *have* found so far is...

o) The Sun 6767A PCI->FC HBA is not "supported" by IBM (with a Shark) for
anything but MPxIO (=STMS).  At least that's what they tell us -- never mind
that it seems to work fine with SDD & DMP also so far.  So now we've brought
in QLogic and JNI cards.  More testing will ensue...

o) IBM's setup guide for using STMS says it only supports 2 paths, if you
have more than that you need to disable the others.

o) From a purely aesthetic point of view, STMS is nice because when it
creates its virtual path to the LUNs, it removes the physical path from
"format" output.  So if I have 6 LUNS attached, I see 6 devices.  With SDD I
actually see all 4 physical paths to each LUN, plus the virtual path, or 30
devices.  Very cluttered and confusing.

o) STMS only has settings for "None" and "Round-Robin" as its concurrent
path options.  The others have "Load Balance", which tells me that, at least
in theory, they're doing some sort of performance monitoring on the buses to
decide where to send your I/O.

o) STMS is relatively new (Solaris 8).  So it's not an option for my 2.6

That's as far as we've gotten for now.  I'll let you all know if someone
comes out a winner.  Further comments, ideas, refutations are still welcome.


-----Original Message-----
From: Jeff Germain []
Sent: Friday, July 09, 2004 4:05 PM
Subject: IBM SAN, HBA, Multipathing & Volume Mgmt

Sun Mgrs,

We have purchased an IBM ESS 800 (Shark) SAN [done deal; no comments there
:-)] and will be attaching multiple Sun systems to it, hopefully all Solaris

We have purchased Sun X6767A HBA's for testing.

We are now looking at MultiPathing options.  Looks like:
o) Veritas DMP

And, Volume Mgmt:
o) Veritas VxVM
o) Sun Volume Mgr (aka DiskSuite++)

There's also a possibility that A) we'll *need* to attach Solaris 2.6
systems (hope not); and B) that we'll be clustering (probably VCS, less
likely SunCluster).

Q: Any thoughts on the features/performance/compatibility/management of the
MultiPathing software?  All of them will be essentially be free to us, so
cost isn't an issue (however, the "free" part of VxDMP assumes we purchase
VxVM, which it seems like we're willing to do).  I think in any case we'll
be dealing with *all* of Sun, IBM and Veritas, so reducing the number of
vendors, though desirable, probably won't happen.

Thanks for your thoughts,

sunmanagers mailing list
Received on Thu Jul 15 15:07:34 2004

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