Basic Disk Queries/Bottleneck

[PaulD_1]

Hi

Just wondering if anyone can help with the following:

We have a Proliant DL380 server (W2K SP1) that seems to freeze occasionally for anything from a few seconds to 20 seconds. I have narrowed this down to the to the Perfmon counter Avg Disk Queue length for the D:\ drive (4 disks comprise of Raid5). When this hits 100 you can’t browse the data shares during this prolonged spike and the users experience a freeze/hang until the drop.

HP have said that one of the drives in Array has small number of write errors which maybe causing the problem and if this is the case then great BUT we are looking to upgrade capacity in the ArrayB to 300Gb drives very shortly but don’t want to do this if the server is under disk stress (Avg Disk Queue length). In fact it would probably be cheaper to purchase another server!

1. Is there any way to troubleshoot Disk Queue issue further; i.e. when the spike hits 100% troubleshoot which file/user is could be causing the bottleneck (we are firm of architects so files maybe images/drawings etc so not your typical office documents).

2. We have around 60-80 users accessing various file shares – would anyone say this is too high a figure (CPU is always under 10%, Network Util usually less than 1% and there is always more than 1Gb free RAM)

Many Thanks in advanced for any input.

[Gus Kwong]

I would have thought architect CAD files are quite sequential... But can I check how good/bad is the status of file fragmentation?

[PaulD_1]

Hi!

Recently used 30 day Diskeeper trail on the data drive to schedule a daily defrag for the trial duration. However there is now only currently about 23Gb (5%) on the drive free (410Gb capacity)now maiking defragmenation much harder.

[Gus Kwong · Accepted solution]

Hi Paul,

Can you confirm you are using the Diskeeper Enterprise, please? If it is the Server edition then I am afraid the software wont do the job if you have 300GB in total.

Hope this helps!

ps: if the post helps please kindly assign points. Thanks.

[PaulD_1]

Hi Gus

Thanks for the response. Its Diskeeper Server Standard; didnt realise about the capcity restrictios.

Cheers

[PaulD_1]

Apparently standard server edition will defrag up to 2 TB. However, any volume above 150gb would benefit more from the enterprise version because larger volumes take longer to defrag. So back to the original question I guess!!

Thanks

[Gus Kwong]

Paul,

I can assure you if you have 300GB the Diskeeper Server edition rather than Enterprise and when it is running the server becomes almost unsusable --- well, that's what happened to the Webtrends7 server (with 300GB also) I used to run. Not only that, the engine ALWAYS hang half way through the defrag.


However, if you are positively sure the file fragmentation is not an issue then you would need to check out the usage pattern of the file access --- you may need to buy a Battery Backed Write Cache for the DL380 to increase the speed of dynamic write.

[PaulD_1]

Thanks Gus. Will need to upgrade the disks get some extra space and run full defrag (windows version or otherwise).