641 controller, FAST write but SLOW read? Help!

[Tyler Bishop_1]

Hi, I have a HP 641 Controller with the 128mb cache + battery backup. The controller has a raid 5 array consisting of 5x72gb 10k drives with a Stripe size of 16kb.

I can write a 4GB test file to the array at between 190 and 240MB/s, however when I try to read any file big or small the array is slow to respond and only averages 5MB/s.

I've benchmarked the drives individually and all of them average between 58 and 64MB/s at 8ms seek. Array is over a month old and has been like this since day one. Any ideas as to why my read performance is dog slow?

Some people have said the CPU on the 641 may be to slow for raid5, I find this hard to believe, even a slow scsi card should be able to read at at least 80MB/s from a array such as this.

HP 641 Fiwmare 2.84 (192MB total cache) Set at 75% read /25% write

[Tyler Bishop_1]

Please help!

[Rob Leadbeater]

Hi,

What OS are you using ? What drivers ?

Cheers,

Rob

[Tyler Bishop_1]

Windows Server 2008 x64

Controller firmware rev b v2.84

Driver hp 6.8.0.64 12/7/2007

[Rob Leadbeater]

Hi,

You might want to try a newer driver...

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareIndex.jsp?lang=en&cc=us&prodNameId=348490&prodTypeId=329290&prodSeriesId=3745263&swLang=13&taskId=135&swEnvOID=4024

Latest is 6.8.0.64 (F) (18 Aug 2009).

Windows 2008 support wasn't added until 6.8.0.64 (B) (25 Feb 2008).

Hope this helps,

Regards,

Rob