topic VA7400 in Disk Enclosures

VA7400

Ken Hawkins — Wed, 05 Jun 2002 16:46:03 GMT

Recently replaced a FC60 with a VA7400, and the through put went down the tubes. FC60's I/O was around 20 msec, the VA7400's around 70-75 msec. Running firmware 14. Found the alternate path incorrect, and this dropped th I/O to around 35msec. The VA7400 has 55 - 73GB drives. Any ideas as to the slow thru-put??

Re: VA7400

Pete Randall — Wed, 05 Jun 2002 17:02:17 GMT

Ken,

The 73GB drives are 10K rpm. By any chance were the FC60 drives 15K rpm? They're anywhere from 20 to 40 percent faster.

Pete

Re: VA7400

Vincent Fleming — Wed, 05 Jun 2002 19:06:50 GMT

There were a variety of performance improvements made in the HP15 FW release. The current release is HP16.

HP16 is now a mandatory upgrade for the VA7400 (optional on the VA7100), so since you're on HP14, you should schedule the upgrade as soon as you can.

One big thing to note about performance as well... LUNs on Redundancy Group 1 (RG/1) should be accessed via controller 1 (MC/1) and LUNs on RG/2 should be accessed via MC/2... this will increase performance. You can use LVM to set the primary path.

With these two items, I bet your performance improves quite a bit.

Good luck!

Re: VA7400

Peter Mattei — Thu, 06 Jun 2002 06:06:58 GMT

Another point is the RAID levels. If you were using your FC60 in RAID10 and are now running the VA7400 in AutoRaid and fill it far >50% of the available raw space you will have most of your data in RAID5DP.
RAID5 by design has a lower write performance in OLTP load due to the parity handling.
So to get a fair comparison both arrays should use the same RAID level.
The VA performs best when set to RAID10 or in AutoRaid mode with less than 50% of the raw space allocated to LUNs and when all LUNs are accessed via the performance path (also read the users guide starting on page 36 on:
http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&docIndexName=manuals&locale=en_US&prodTypeId=12169&prodSeriesId=64100&prodSeriesName=hp+surestore+virtual+array+7400

Re: VA7400

Ken Hawkins — Fri, 28 Jun 2002 17:20:24 GMT

The HP16 is Definitely the fix for the above problem. After the upgrade the VA7400 is now out performing the FC60 hands down.