goliveuk
asked on
High value of the Avg. Disk Queue Length
Hello, we are running Small Business Server 2003 on HP Proliant 380G3 and there is problem with the average values of the Disk Queue Length. There is moments when the average value is over 2 and the people on the workstations are complaining the everything is too slow. We just upgraded the memory so now the memory utilization is under 30%. Is there any way to reduce the average value for the Disk Queue Length?
goliveuk,
http://technet.microsoft.com/nl-be/sysinternals/bb896653(en-us).aspx
this was the one I was looking for
suppsaws
http://technet.microsoft.com/nl-be/sysinternals/bb896653(en-us).aspx
this was the one I was looking for
suppsaws
>Is there any way to reduce the average value for the Disk Queue Length?
Yes - as a general rule - add more discs. How many users on your server and what apps are you running? Presumably Exchange at the least. Can you also provide more information about the physical configuration of the server?
Moments of Disk Queue Length >2 is OK - high disk queue length for extended periods is not. There are other counters you need to check:
If % Disk Time is over 55% when the Avg. Disk Queue Length counter is over 2 per physical disk indicates an I/O bottleneck
Avg Disk sec/read and Avg Disk sec/write should be under 10ms. Over 20 ms indicates a possible bottleneck
And many, many more.
This is a good article to review before you go too much further: http://www.oreillynet.com/pub/a/network/2002/01/18/diskperf.html
Yes - as a general rule - add more discs. How many users on your server and what apps are you running? Presumably Exchange at the least. Can you also provide more information about the physical configuration of the server?
Moments of Disk Queue Length >2 is OK - high disk queue length for extended periods is not. There are other counters you need to check:
If % Disk Time is over 55% when the Avg. Disk Queue Length counter is over 2 per physical disk indicates an I/O bottleneck
Avg Disk sec/read and Avg Disk sec/write should be under 10ms. Over 20 ms indicates a possible bottleneck
And many, many more.
This is a good article to review before you go too much further: http://www.oreillynet.com/pub/a/network/2002/01/18/diskperf.html
ASKER
Will and upgrade with battery-backed write cache solve that problem ?
ASKER
Yes there is exchange running, and the users are over 15
How many discs are there in the server and how are they configured? (RAD 1, RAID 5 etc).
ASKER
There are three disks - RAID5
What other applications are running? Your system should cope with ease with 15 users - although be aware of the performance hit caused by the RAID 5 write penalty. Is there a really heavily disc intensive application installed?
ASKER
There is not other heavy application. How can I monitor different instances on the server 2003 and determine which process (or user) is causing the Average Disk Queue Length to rocket high from time to time?
ASKER CERTIFIED SOLUTION
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Thanks! What fixed your problem in the end?
Did you already check which process is causing the disk slowdown?
You could use Diskmon/filemon or check the I/O writes I/O reades on the task manager.
Regards,
suppsaws