VM exhibiting 100% disk busy time, large disk queue lengths

Question

Hi everyone,
We have a .VHD workload residing on a logical 2 x 136Gb RAID1 mirror pair of disks.
The .VHD file is 130Gb (with 70Gb of free space)
The Virtual Machine is running Windows 2008 R2 SP1, 4 cores and 8Gb of RAM and is exhibiting 100% disk busy time and disk queue lengths of anywhere between 14 and 44
I'm assuming this is because there is virtually no disk space on the logical drive. Ops Mgr 2012 R2 reports high memory pages/sec
So we backed up the .VHD workload, broke the RAID1 Mirror and inserted 2 x 300Gb  as a RAID1 mirror and restore the .VHD / VM
The Logical disk has 50% free disk space, however the VM is still exhibiting 100% disk busy time and the above disk queue lengths.
It is running on a Windows Server 2008 R2 SP1 HP Proliant Server running the Hyper-V role under Server Core
Any ideas most appreciated.

Answer 1

Hi,
The mirror array doesn’t improve the disk performance but only for the disk redundancy, base on my experience some application frequent operate the large small files often
can use the large disk resource, if you can’t sure the high disk IO cause by the guest vm or host computer, you can use the Resource Monitor first to identify which process handled the high disk resource, then do the further troubleshooting:
The third party Resource Monitor use example:
How to use the Resource Monitor in Windows 7 & Windows 8
http://www.7tutorials.com/how-use-resource-monitor-windows-7
Hope this helps.
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