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HP AutoRAID 12H performance

Maarten van Maanen
Regular Advisor

HP AutoRAID 12H performance

We use an Oracle 8 database on a HP9000 K370-system with a 12H with 6 18Gb HDD's.
Using arraydsp -r a get the message:
Add another disk because the disks are being overworked.

I/Os are stacking up in the command queues for the disks. This creates a
bottleneck which can be solved by adding another disk. The new disk will
take some of the workload off the existing disks and improve performance.

When using arraydsp -r I get similar results:
Vendor ID = HP
Product ID = C5447A
Array serial number = 00000013C8F1
Performance Metrics
--------------------------------------------------------------------------------
Requested Period = 09:00 07/06/2000 to 12:00 07/06/2000
Actual Period = 09:15 07/06/2000 to 12:00 07/06/2000
Interval = 4

Out-of-Spec Indicator = *
--------------------------------------------------------------------------------
Drive Relocate Working Cache SCSI

Difference Blocks Set Util Q

07/06/2000
09:15 1.000 0.000 0.570 0.000 *107.000

10:15 1.000 0.000 0.590 0.000 *111.000


This would mean I/O-request are stacking up in the SCSI-queue. With 6 HDD the SCSI parameter should not be higher than about 30. In practice it's always around 90-110. I am always getting results like this ever since the Oracle has been in production-use.
I'm using both 12H-controllers with 96Mb each and they are cross-linked and both are used.
Is there an other way to improve performance ?

Maarten van Maanen
Netherlands

4 REPLIES
Frank Skibbe
Advisor

Re: HP AutoRAID 12H performance

Maarten van Maanen
The best way to increase performance is to check the following things.
1)If you had the firmware HP54 or higher you can switch the Diskarray in 4 diiferent mody. The normal modus which is default and Highperformance modus. The best way is to switch to High performance modus.
2) Check with arraydsp the space of RAID 1/0 space. If it is two small than you need more disk space to get higher performance.
3)Load blancing must be used. The normal config is 4-6 Lun. 2-3Lun's on each controller.
Brian M. Fisher
Honored Contributor

Re: HP AutoRAID 12H performance

An inexpensive option would be to add several 9GB used disks to the AutoRAID. This would definately speed performance at a minimal cost (~$600 per).

Brian
<*(((>< er
Perception IS Reality
Mike Seerden
Advisor

Re: HP AutoRAID 12H performance

We once considered the 12H (about 4-5 of them) to run our Oracle production but went EMC instead. The thing we learned from HP is to run the AutoRaid at 50% capacity or less. This will keep the data in a RAID 0/1 config. After 50% it starts putting the data in a RAID 5 config thus slowing things down. If you can afford more disk then do that to increase the size so your data doesn't take more than half of the volume size.

Re: HP AutoRAID 12H performance

During a working session with a performance guru, i learned that with the evolution of the disk technologies to more and more and more data on one disk (PC market need!), we MUST consider today the number of I/O needed per seconds versus the capability of one drive (~ 60 to 100 I/O's/sec.). Choose how many disks you need, multiply by 2 for raid1.
After that just control that there is enough Gigs!!!
The more disks you add, the more perf you will have.
Don't bother about the 'wasted' space, someone in your company will need it one day!!!
Nothing is impossible, just have to find how to!!!