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disk queue length

i have a hp raid 10 array with 6 disks, what is the threshold for disk queue length? is it 2 per disk? so in my case it would 12?
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Kylo Ren
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Kylo Ren
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gmbaxterCommented:
If the average disk queue length is greater than twice the number of disks in the volume/array then the storage is the bottleneck, so in your case yes 12.

You could certainly look into the average read and average write indications separately to get further information.
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David Johnson, CD, MVPOwnerCommented:
@gmbaxter: Yes that is the theory.. Whether or not it affects the user experience is another question. On my drive E (6 Drives in a Storage Space) the current disk queue is 58 (I am pausing a Vmware workstation), yet it doesn't impact my other running applications..
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gmbaxterCommented:
Yes it does depend on the application in that respect. In a 16 disk array running user home folders I've seen queues of 35 severely affecting performance.

The main thing to do is to analyse the issue, if you view the application as a user at peak times and you think there is a problem, then look into where the problem originates from. If however things are running smoothly, then don't just throw money at a san/array just because a graph says so.
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MaxEL_UACommented:
Here is a TechNet article for bottleneck calculations
http://technet.microsoft.com/en-us/library/dd723635%28v=office.12%29.aspx
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