Zero Detection in Vmware with Win2008 or Linux

[fritz]

Hello!

We are planing to buy a Storeserv 7200 and now we have a
question about the Zero Detection.

Can we use the Zero Detection Feature inside a VM?
For example if i delete inside a VM (Win2008 Server),
a big file with the file explorer, will this space be reclaimed
automatically?

Thank you for your help + regards,
Fritz

[skumflum]

Windows 2012/8 and newer has improved automatic disk optimization beyond simple defrag. The Optimizer in Windows 2012/8, now takes care of maintenance activities like compacting data and compaction of file system allocation for enabling capacity reclamation on thinly provisioned disks.

You can use 3. party tools in older Windows like http://www.raxco.com/business/products/perfectstorage

I don't how this is done in Linux, sorry

Sphere 5.0 introduced the VAAI Thin Provisioning Block Space Reclamation but you have to run this manual. My guess would be that we will se this done on the fly in later versions. (Hyper-V in 2012R2 is able to do that)

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2014849

[hdtvguy]

I am not sure about Windows 2012, but for 2008 you would need to run sdelete or something that will zero unused blocks that are freed up. We have a project to get that implemented to free those blocks back up.

[skumflum]

I Think you will find most of your answers in this document http://h20195.www2.hp.com/v2/GetPDF.aspx%2F4AA3-8987ENW.pdf

3par thin technologies.

There is also some notes about Linux

[Richard Siemers]

Yeah check out the doc skumflum linked, it is up to date and has good info for Linux, which basically is to use a mount option for the filesystem and it will keep itself thin in real time.

[fritz]

Hello!

Thank you for your help.
I read already the "HP 3PAR Thin Tehcnologies" document.
And in my point of view, a automatic Zero Detection with W2008
will not work.

But the HP partner said it will work with VMWare 5.5 (and W2008 as VM).

[wagnerse]

Hello fritz,

the feature will not work with vSpere 5.5 and Server 2008. This is because 2008 does not write zeros down to the Storage. You have to use sdelete. 2012 has T10UNAMP built in, but can use it only at direct connected LUNs not on VMDKs or RDMs. Here we have to ask VMware to support T10UNMAP with their virtual SCSI Adapters.

regards
Sebastian

[fritz]

Thank you for this clear statement!

regards,
fritz