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How do I get the Nimble unit to show the correct amount of space used/free?

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dejvnull49
Advisor

How do I get the Nimble unit to show the correct amount of space used/free?

Hi all!

We have 2 Nimble units and we have just jumped of the Exchage 2013 bandwagon (to many bugs and major problems with Quest migration tool) and will choose to stick with a Windows 2008 R2 + Exchange 2010 solution running on Windows 2012 Hyper-V.

Everyting works great with the Windows Integration Toolkit and the Volume Collections for snapshotting our new Exchange 2010 environment.

The Exchange system is set up with 2 database volumes and 1 log volume for both databases.

What I do wonder about is that on the log volume after a snaphot with verify has been performed and the Exhange 2010 logs have been truncated, the volume on the Nimble Storage GUI does not show the correct amount of free space. I am guessing this has to do with the storage system not being able to reclaim the now free blocks back from Windows 2008 R2.

So even with the WIT installed does this not in some way tell the storage system that X blocks are free and can be reclaimed?

Is there some other way to do this in Windows 2008 R2. I know that Windows 2012 releases free blocks back to the Nimble storage system but I don't know how we get this done on Windows 2008 R2.

Here are two pic to demonstrate... I have marked with red the Storage sytemem VS Windows 2008 R2 and what they present as free...

Pic 1

Nimble-forum-question-pic-01-20130707.PNG.png

Pic 2

Nimble-forum-question-pic-02-20130707.PNG.png

Anyone with a few pointers feel free to help :-D

Cheers!

/Dave

8 REPLIES
jrich52352
Trusted Contributor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

great question. I was told when I got my unit that it would clean up with 2k8R2.. I looked in to the OS side and the Trim feature is on, you can find this by running the following command in an elevated prompt

fsutil behavior query disabledeletenotify

it should return 0, which means it will send the delete command back to the storage device.

someone from nimble might respond, but you should probably give support a call.. I'd be interested to see what they say

dejvnull49
Advisor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

Hi Justin!

Hmm, I recall that command from Win7 and SSD's. Running it on my server gives me the return value of 0. So that might not be they only issue. I have talked to the support tech here in Scandinavia and he sent ne a link, but it was for the wrong OS (Win8/Win2012) so I asked him to resend the what he has regarding Win2008-R2.

I'll post when I get a solution.

Thanks for your help!

/Dave

jrich52352
Trusted Contributor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

hmm well it will be interesting to see what they show, but as far as the OS goes, it should be all set. I would imagine that the OS (because of that SSD setting) it should be zeroing out the bits, and passing that on to the storage device... they refer to that setting as "for SSD or thin provisioned volumes"

lets see what they come back with

ndyer39
Honored Contributor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

Hi David/Justin,

From the thread of comments it appears that you're referring to something called SCSI Unmap - which is the ability for an OS to send a command to the storage array to "re-thin" the volume down to the required size on the block level.

In Windows, SCSI Unmap was introduced in Windows 2012 as native support - it is not possible to do such "re-thinning" in Windows 2008/R2 or Windows 7. From a Nimble OS point of view, this was introduced at the end of 2012 in NOS 1.4.4, I believe.

The TRIM command is not something that Nimble recognises as it's designed for direct connected SSD drives that support the command, to allow it to Garbage Collect blocks from SSD drives for optimum use. (TRIM - Wikipedia, the free encyclopedia).

dejvnull49
Advisor
Solution

Re: How do I get the Nimble unit to show the correct amount of space used/free?

Well here is the solution provided by Mark Fulton at Nimble Storage by way on Stephen D'Amore, both technicians at Nimble Storage.

Hi David,

I was passed the below thread from my colleague Steve to provide you with some more info.

The below mentioned fsutil command is supported for local SSD’s only and not thin provisioned SAN volumes attached via iSCSI under Windows 2008 R2.

NTFS has been updated in Windows Server 2012 with online (periodic) discard support to inform underlying SAN storage of vacated free blocks on the file system, see P. 16 of the following Microsoft white paper:

http://download.microsoft.com/download/A/B/E/ABE02B78-BEC7-42B0-8504-C880A1144EE1/WS%202012%20White%20Paper_Storage.pdf

  1. Optimization. Windows Server 2012 provides a new API that enables applications to release storage

when it is no longer needed. NTFS issues trim notifications when appropriate in real time. In addition,

trim notifications are issued as a part of storage consolidation and optimization, which is performed

regularly on a scheduled basis.

Windows 2008 R2 supports “batched discards” via usage of the sdelete utility - When run with the -z option and the appropriate drive letter specified, the tool will write zeroes to the unused blocks on the iSCSI volume. After the tool has run, the array will then report volume space usage figures matching those of the host filesystem.

So, the key differences here are that Windows Server 2012 will report the vacated space to the storage (via SCSI unmap) on the fly, whereas earlier Windows releases require a tool to be manually run to clear these out. Note that using sdelete -z is I/O intensive, so we recommend it to be run as a scheduled task during a quieter period where the array is under less load.

I’ve also attached a KB that describes this in further detail, see the chapter on “thin provisioning space usage”.

 

Let me know if you have any questions.

Thanks,

  Mark"


This can also be read up on on the Nimble Storage KB document:

Volume Space, understanding space usage

KB-000040

Apr 5, 2013


Hope this can help someone else!


/Dave




jrich52352
Trusted Contributor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

hmm still sdelete huh... bummer... oh well at least its something..

thanks for the update dave

nick thanks for the explanation

sdamore72
Occasional Visitor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

Thank you for uploading the solution, David!

Take care,

Steve

jfeierfeil131
Occasional Visitor

Re: How do I get the Nimble unit to show the correct amount of space used/free?

You also need to make sure you have the most recent MS hot fixes installed on W2K12 as there was some issues encountered with getting unmap to work in a predictable way. You'll need http://support.microsoft.com/?id=2779768 as well as some recent hot fixes that are due out in July.