Monday, 30 September 2013

Offload Data Transfer (ODX) in Windows Server 2012

I've been working on a nice Dell R720 host based Hyper-V cluster this week with a Dell Compellent array providing the storage.

One of the things I was looking forward to with this job was getting hands on with the ODX feature of the Compellent.

ODX (Offload Data Transfer) is a feature found on some of the newer storage arrays that helps with large file operations by (in simplified terms) keeping the transfers within the array rather than passing the file to the source then destination servers then back to the array.

The first thing to do (assuming you know the hardware supports it) would be to check that the OS and it's software components supports ODX.

Now this is a Windows Server 2012 and 2012 R2 only feature so if you're on 2008 R2, time to upgrade.

From a PowerShell prompt, run the following command:
Fltmc instances

Take a note of the volume name of either the drive, or in my case the CSV volume you want to check.  Then run:
Fltmc instances -v <Volume Name>

e.g. Fltmc instances -v C:\ClusterStorage\Volume1

This will give you the filter names that you will need to check.
Run this command, replacing the <Filter Name> with those shown by the previous command.

Get-ItemProperty hklm:\system\currentcontrolset\services\<FilterName> -Name "SupportedFeatures"

So for my two filters of FsDepends and MpFilter I get the following output:

The property that needs checking is "SupportedFeatures".  If this has a value of 3 then ODX is supported and you're good to go.  Anything else and you'll need to look into it further.

Lastly, check if ODX is enabled on your server using this command:
Get-ItemProperty hklm:\system\currentcontrolset\control\filesystem -Name "FilterSupportedFeaturesMode"

If it returns a "FilterSupportedFeaturesMode" other than 0 as shown below then ODX isn't enabled.

Run this to enable ODX:
Set-ItemProperty hklm:\system\currentcontrolset\control\filesystem -Name "FilterSupportedFeaturesMode" -Value 0 -Type DWord

Or this to disable ODX if needed:
Set-ItemProperty hklm:\system\currentcontrolset\control\filesystem -Name "FilterSupportedFeaturesMode" -Value 1 -Type DWord

In order to demonstrate to the client that ODX was indeed enabled and more to the point worth having, I modified the script on Hans Vredevoort shows on his blog post discussing ODX testing between 3Par and Compellents here:

I ran the script which loops through creating 10 x 50Gb and 10 x 475Gb fixed disks with ODX enabled and then does the same but with ODX disabled.

This was the timings from the test:

With ODX
12.6 seconds for 10 x 50Gb vhdx files
84.2 seconds for 10 x 475Gb vhdx files
96.8 seconds total for all vhdx files

Without ODX
1015.5 seconds (nearly 17 mins) for 10 x 50Gb vhdx files
8615.8 seconds (just over 2 hours) for 9 x 475Gb vhdx files (N.B. I ran out of disk space for the 10th)
9631 seconds or 2.7 hours total for all vhdx files

There is a MASSIVE difference in creation times!

ODX is a feature well worth having in my opinion.  What I really can't wait for is ODX support with SCVMM libraries in the SCVMM 2012 R2 release!!

I've uploaded the ODX Test script to SkyDrive here:

1 comment:

Anonymous said...

Tried running it too.. creating a 50Gb file on 3PAr with ODX ~ 3.05Min, WITHOUT! ODX: 2.39Min