topic Re: VA7400 performance issue in Disk Enclosures

VA7400 performance issue

Hoang Chi Cong_1 — Thu, 25 Aug 2005 05:16:20 GMT

Hi all
I have to face a trouble with my system:
We have one main enclosure and one JBOB disk enclosure was connected to the main array enclosure DS2405).
Currently, the VA performance is very slow (Disk's performance almost 100%)
I am considering the firmware of the VA's component:
1. VA firmware: the current controller's is HP19.
2. The LCC Controller's is HP04
3. The disk is HP09
My question are:
1. Are there new firmware available now for each item to improve the VA performance?
2. The best size rate: Unallocated/Total in a RG?
Can anybody explain for me this fomular:
Formula: Number of disk in RG * 2 / Number of LUNs in RG = queue_depth

What is queue_depth and how it effect to the VA performance?

Any answer is much appreciated!
Thanks in advance!

Re: VA7400 performance issue

Uwe Zessin — Thu, 25 Aug 2005 06:06:12 GMT

Queue Depth is a setting on the host's SCSI driver and defines the number of outstanding I/Os on a LUN.

The formula suggests that the VA can support up to about 200 outstanding I/Os. About 100 disks *2, to keep each disk busy. As the queue depth setting is per LUN, you need to divide by the number of LUNs in order not to overrun a controller.

Re: VA7400 performance issue

Torsten. — Thu, 25 Aug 2005 06:25:31 GMT

regarding the firmware: current versions are HP20 for the VA and HP05 for the LCC. Disk firmware depends on the specific model. ask hp for an update. Very important for performance is the mode, which can be just mirror or raid5dp. Don't know about the last firmware influences performance.

Re: VA7400 performance issue

Mahesh Kumar Malik — Thu, 25 Aug 2005 07:05:37 GMT

Hi

Please set "Write Cache" to OFF in controllers. Performance should improve.

Regards
Mahesh

Re: VA7400 performance issue

Hoang Chi Cong_1 — Thu, 25 Aug 2005 23:15:28 GMT

Thanks to all.
Seems that difficult to assess my VA systems.
Now I am preparing for making a plan to improve the VA.
Thus, so kind if you send me any technical document talk about VA 7400 performance. I need the evidence and show it to my manager before reoganize the VA.

Thanks in advance!

B&Rg
Hoang Chi Cong

Re: VA7400 performance issue

Hoang Chi Cong_1 — Fri, 26 Aug 2005 00:06:21 GMT

To Mahesh Kumar Malik:
I don't thinks so, the Write Cache can not modify in controller setting.
I have read the VA 7400 service guide and it shown the Cache Hit and Read/Write IOPS.
My VA now has 29 disks and the Queue Full Threshold is 750.
The VA was configured in AutoRAID mode. We can not run in RAID 0+1 mode because don't have enough disk!

Any idea?

Re: VA7400 performance issue

dave daniels_2 — Fri, 26 Aug 2005 14:52:06 GMT

Send me an email and I can send you the VA perf analysis document. To large to attach.

-Dave
daved@elite-group.us

Re: VA7400 performance issue

Hoang Chi Cong_1 — Sat, 27 Aug 2005 03:35:38 GMT

Thanks to dave!
My email : conghc_itca@vbard.com
Please Cc to a backup mail: hoangchicong2005@yahoo.com

Thanks in advance!

Have a nice weekend!
B&R
Hoang Chi Cong

Re: VA7400 performance issue

Srinivasa_6 — Tue, 01 Nov 2005 05:09:48 GMT

The latest VA firmware is HP22 but I believe there were no performance improvements in either HP20 or HP22 (Dunno what happened to HP21??). I would recommend you upgrade the LCC firmware to HP05, since HP04 had FC loop problems which, I am guessing, could bottleneck the FC loop on which the drives reside.
Also, when you say that performance is low, are you experiencing application timeouts on the host side? May be you can tweak around the host HBA driver settings. I would also suggest you to have a HP customer engineer look at the controller logs and ask him to adjust the array host port "Queue Full Threshold" accordingly. May be your array QFT setting is a bit high.

Re: VA7400 performance issue

A.G.M. Velthof — Tue, 01 Nov 2005 07:39:11 GMT

The allocated space should be > 50% of the total capicity.
Did You check that?

Regards, Alfons