RE: New Power8 Disk Perf Issues

Were these 8 drives, (2 and 6) all in the CEC.
If so, then you need a DASD controller with decent cache.

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Roberto José Etcheverry Romero
Sent: Tuesday, August 26, 2014 12:45 PM
To: Midrange Systems Technical Discussion
Subject: Re: New Power8 Disk Perf Issues

CEC with 0 cache could be used for VIOS, if you're hosting all storage in the SAN, there is very litle I/O from VIOS to its rootvg...
I just came back from a client where somebody sold a solution where VIOS lives in 2 mirrored SSDs and IBM i was supposed to live in 6 spinnys served by VIOS... They gave up when performance wasnt even near what it should be and got a v7000...


On Tue, Aug 26, 2014 at 12:13 PM, Steinmetz, Paul <PSteinmetz@xxxxxxxxxx>
wrote:

Why would you pick a backplane option with 0 write cache.
History has proven that the CEC with 0 write cache will be a
performance issue.
History also has shown that the CEC should be avoided for a production
lpar.

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Jim Oberholtzer
Sent: Tuesday, August 26, 2014 11:10 AM
To: 'Midrange Systems Technical Discussion'
Subject: RE: New Power8 Disk Perf Issues

Thanks for the clarification Sue. The literature is not clear on
those point.

--
Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Sue Baker
Sent: Tuesday, August 26, 2014 9:44 AM
To: midrange-l@xxxxxxxxxxxx
Subject: RE: New Power8 Disk Perf Issues

"Jim Oberholtzer" <midrangel@xxxxxxxxxxxxxxxxx> wrote on Mon, 25 Aug
2014
18:24:28 GMT:

We know that P8 will use internal storage, except, as I understand
it, if you have the back plane split so you can run dual VIO Servers.

No, the split backplane is supported by IBM i so you do not have to
run dual VIO servers. This means you could have VIOS for NPIV using
1/2 the disk bays. Then sitting right beside an IBM i LPAR using the
other 1/2 of the disk bays.

Then you must use external storage.

Even if you do dual VIOS, there are card slots for disk IOAs which can
be dedicated to an IBM i LPAR. I'm not sure why you say with split
backplane storage must be external SAN. Unless you really meant
storage will be external to the CEC.

So
it's about half right. Even then I think you might get away with
internal storage but it would be A) slow and B) very limiting so
certainly not recommended.

--
Sue
IBM Americas Advanced Technical Sales Support (ATS) Power Systems
Rochester, MN
--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe,
unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take
a moment to review the archives at http://archive.midrange.com/midrange-l.


--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe,
unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take
a moment to review the archives at http://archive.midrange.com/midrange-l.

--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing
list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe,
unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take
a moment to review the archives at
http://archive.midrange.com/midrange-l.

--
This is the Midrange Systems Technical Discussion (MIDRANGE-L) mailing list To post a message email: MIDRANGE-L@xxxxxxxxxxxx To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/mailman/listinfo/midrange-l
or email: MIDRANGE-L-request@xxxxxxxxxxxx Before posting, please take a moment to review the archives at http://archive.midrange.com/midrange-l.