topic Re: Poor Performance on VA 7110 in Disk Enclosures

Poor Performance on VA 7110

Delrish — Mon, 21 Feb 2005 15:57:20 GMT

Hi,

I have a VA 7110 attached to a HP9000 server.
The problem is poor performance.
I setup a test. I copied a 1.5 GB file from server’s local scsi hard disk to a LUN that made on array. After that I copied that file from array to Server’s HDD. And finally copied the file form a LUN on array to another LUN. I made a logical volume for each LUNs. I mean in this test, the file copied from a LV to another LV.
I calculate the speed by measuring the time took for completing the each test.

HDD to Array : 33MB/s
Array to HDD: 17 MB/s
Array to Array : 44 MB/s

I read in HP documents that VA 7110 throughput is 200 MB/s
This is my Array configuration:

##Port Settings:
Topology = FABRIC Attached
Port Data Rate = 2Gb
Queue full Threshold: 1024
Port Behavior: HP-UX
##Array Settings:
Raid: Raid 1+0
Data resiliency: High performance
Hot Spare Mode: Automatic

What is the problem?
Please advice.

Alire

Re: Poor Performance on VA 7110

Leif Halvarsson_2 — Tue, 22 Feb 2005 02:58:52 GMT

Hi,

I belive the 200MB/s relates to the FC interface and, perhaps to cached read/writes, not reading/writing from disks.

The VA7110 uses something called AutoRaid, part of the array works in Raid 10, the rest in Raid 5DP (Double Parity). Raid 5DP has a very high write overhead which may be one reason for your limited performance. If I have understand correct, it is possible to configure the array for Raid 10 only. This may give better write performance but, to the cost of disk space.

Re: Poor Performance on VA 7110

Bernhard Mueller — Tue, 22 Feb 2005 04:48:55 GMT

Alire,

with RAID1+0 setting and 2Gb Fabric attach, there are basically just the two major options to increase VA performance: more cache memory, more disks.

Regards,
Bernhard

Re: Poor Performance on VA 7110

Delrish — Tue, 22 Feb 2005 07:12:43 GMT

Thank You,

This array has 15* Scsi 10k Hard Disk.
In this situation (This Platform and the configuration I determined in my first email), Is this performance acceptable or not?
I think 33 MB/s is too low for this array.
What is your idea?

Alireza

Re: Poor Performance on VA 7110

Delrish — Thu, 31 Mar 2005 08:03:53 GMT

Thank you