Disk Queue Length Average is High

Question

_{Sunday, February 24, 2019 1:34 PM}

Dear Support,

We have file server on Windows Server 2012 R2. 

Shared folder has been kept on Storage LUN mapped to file server.

have been facing performance issue. Disk queue length is high approximate 50.  LUN Size 3 TB and free space 500GB.

Please let us know, how to fix

Thanks,

Ritesh

R!t@$#

All replies (5)

_{Monday, February 25, 2019 4:49 AM ✅Answered}

Hi Leon, Thanks for quick response. We have observed the issue of high disk queue length when backup run. Please let us know how to calculate requirement of I/O for file server LUN. So we can arrange storage LUN with required I/O. Thanks

R!t@$#

_{Sunday, February 24, 2019 2:41 PM}

Hello Ritesh,

There can be many many reasons to why there is a disk queue length.

To pinpoint the root cause of the disk queue length I would suggest you monitor the file server (Windows Server 2012 R2) and storage system or the LUN for a longer period, this way you may be able to see if there are any patterns in the slowness or how the disk queue length behaves.

In general when there's disk queue length, it's the disks that cannot keep up with the required I/O.

If you didn't already, you can monitor your file server (Windows Server 2012 R2) with the builtin Performance Monitor, below are some links that may be of help.

**Configuring Windows Performance Monitor to Capture Disk I/O Activity and Potential Disk Issues
**https://www.smartertools.com/blog/2016/07/15-configure-perfmon-to-prevent-disk-issues

Windows Performance Monitor Disk Counters Explained
https://blogs.technet.microsoft.com/askcore/2012/03/16/windows-performance-monitor-disk-counters-explained/Also if your 3TB LUN is running on slower disks (non-SSD), you could also try optimizing this by moving the data to faster disks (SSD).

Best regards,
Leon

Blog: https://thesystemcenterblog.com LinkedIn:

_{Tuesday, February 26, 2019 2:03 AM}

Hi,

Awaiting for your response.

Thanks,

R!t@$#

_{Tuesday, February 26, 2019 9:50 AM}

Hi Ritesh,

It can be difficult to know the I/O requirement as the disk usage can be very jumpy, but the best way is to monitor your LUN and see what is the average I/O usage, and then set a limit that is well above that average usage.

Blog: https://thesystemcenterblog.com LinkedIn:

_{Wednesday, February 27, 2019 10:05 AM}

Hi, Thanks for your reply. We will check.

R!t@$#