Solved

Disk queue length performance object

Posted on 2013-01-31
5
1,300 Views
Last Modified: 2016-11-23
I have Dell PowerEdge server with 20 x 600GB 10RPM SAS drives in a single RAID6 array.

What is the value of Disk Queue Length performance object that would indicate a bottleneck?

I'm trying to figure if out how much this server can handle

Thank you
0
Comment
Question by:piotrmikula108
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
5 Comments
 
LVL 16

Accepted Solution

by:
choward16980 earned 500 total points
ID: 38841776
Which poweredge, which PERC controller?

My rule of thumb is to have users create time stamps for when they experience I/O pauses by putting an icon that appends a times stamp and username.  I then go back to my performance monitor and review the disk queue length logs and see if the I/O pauses my users are reporting correlate to the log data.


http://www.sql-server-performance.com/forum/threads/average-disk-queue-length.8384/
quote:
"If Avg. Disk Queue Length counter exceeds 2 for continuous periods (over 10 minutes or so during your 24 hour monitoring period) for each disk drive in an array, then you may have an I/O bottleneck for that array"
0
 
LVL 1

Author Comment

by:piotrmikula108
ID: 38841832
PE720XD with Perc H710 mini controller

So since I have 20 drives I could have the queue up to say 35 to be under 2 per spindle? I know I'm simplifying things...
0
 
LVL 16

Expert Comment

by:choward16980
ID: 38842566
Do you know what kind of array the 20 drives are arranged in?  Parity must be considerd as a standard RAID-5 is typically 20-25% parity overhead.
0
 
LVL 1

Author Comment

by:piotrmikula108
ID: 38842587
Raid6
0
 
LVL 16

Assisted Solution

by:choward16980
choward16980 earned 500 total points
ID: 38842695
This guy says >4 for user impact:

http://www.experts-exchange.com/Software/Server_Software/Q_22868359.html

So RAID6 (20 drives - 2 ) * 600GB = 18 drives * 4 = 72.

So by that rule of thumb, >72 would = user impact.

Single controller throughput (6/Gb/s)  pci-e 2.0 (4.0/Gb/s)  so 66% of 72 = 47.52

I would assume anything > 48 would effect the user.
0

Featured Post

Free NetCrunch network monitor licenses!

Only on Experts-Exchange: Sign-up for a free-trial and we'll send you your permanent license!

Here is what you get: 30 Nodes | Unlimited Sensors | No Time Restrictions | Absolutely FREE!

Act now. This offer ends July 14, 2017.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Background Information Recently I have fixed file server permission issues for one of my client. The client has 1800 users and one Windows Server 2008 R2 domain joined file server with 12 TB of data, 250+ shared folders and the folder structure i…
This article explains how to install and use the NTBackup utility that comes with Windows Server.
To efficiently enable the rotation of USB drives for backups, storage pools need to be created. This way no matter which USB drive is installed, the backups will successfully write without any administrative intervention. Multiple USB devices need t…
This tutorial will walk an individual through the process of configuring their Windows Server 2012 domain controller to synchronize its time with a trusted, external resource. Use Google, Bing, or other preferred search engine to locate trusted NTP …

717 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question