Solved

Disk queue length performance object

Posted on 2013-01-31
5
1,297 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

Guide to Performance: Optimization & Monitoring

Nowadays, monitoring is a mixture of tools, systems, and codes—making it a very complex process. And with this complexity, comes variables for failure. Get DZone’s new Guide to Performance to learn how to proactively find these variables and solve them before a disruption occurs.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
Certain exe files will not run in Vista 26 51
Folder Redirection GPO 8 52
disk usage reporting tools 27 54
.NET - find out if application is running on Windows 2012 server 3 35
Ever notice how you can't use a new drive in Windows without having Windows assigning a Disk Signature?  Ever have a signature collision problem (especially with Virtual Machines?)  This article is intended to help you understand what's going on and…
The reason that corporations and businesses use Windows servers is because it supports custom modifications to adapt to the business and what it needs. Most individual users won’t need such powerful options. Here I’ll explain how you can enable Wind…
This tutorial will walk an individual through the steps necessary to install and configure the Windows Server Backup Utility. Directly connect an external storage device such as a USB drive, or CD\DVD burner: If the device is a USB drive, ensure i…
This tutorial will walk an individual through setting the global and backup job media overwrite and protection periods in Backup Exec 2012. Log onto the Backup Exec Central Administration Server. Examine the services. If all or most of them are stop…

733 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