Making sense of Disk Queue Length

[Michael Maher]

Folks,

I'm looking at the performance of a DL380 G2 running as a SQL/Cold Fusion server. I am concerned about Disk Utilisation.

The System Monitor counter 'Current Disk Queue Length' told me that it hit a maximum of 33 overnight. The Microsoft supplied explanation for this counter says . . .

"Requests are experiencing delays proportional to the length of this queue minus the number of spindles on the disks. This difference should average less than 2 for good performance"

Can anyone make sense of this calculation?

How do I determine the number of spindles on my disk (4 x 18.2GB, RAID5, 5i Controller)

Is this disk activity excessively high?

Thanks,

Michael

[Michael Maher]

BTW - the disks themselves are Ultra 3 and the controller is running firmware 3B07