Converting disk from thin to thick

[fransje1975]

I have a problem with converting disks from thin to thick.

This is what i am doing.

I turn off the VM go with datastore browser to the disk and do inflate. I am getting no error and it lookes like that the disk is inflated (disksize is now correct). Only when i am checking in Vcenter the disk is still saying thin. Also i can inflate it again (nothing changes to disksize and Vcenter).

Then i do it with the command line vmkfstools -j the disk is inflating (no errors) but this nothing changing in Vcenter.

Then i do a other disk same procedure and i can inflate the disk, nothing changes in Vcenter only now i cannot inflate it again (option gradeout)

What i am doing wrong ? We are using ESX4i with NFS storage (netapp)

Thanks,

Francois

[paul_xtravirt]

NFS storage supports thin provisioned disks only. It is one of the benefits of NFS.

Check out the following document, page 4

"In the past, thin provisioning has been the default format for virtual disks created on NFS datastores in Virtual Infrastructure 3, and has been available through the command line for block-based datastores."

This quote is still valid for vSphere 4 connected NFS datastores.

http://www.vmware.com/files/pdf/Storage-with-VMware-vSphere.pdf

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[AnatolyVilchins]

Agree with Pual.

I have saw similar problem before here:

http://communities.vmware.com/message/1501841#1501841

BTW - why thick? Company policy?

iSCSI Software Support Department

http://www.starwindsoftware.com

[fransje1975]

I saw that on NFS the standard disk is thin. I cannot find anything saying that i cannot be changed. I tried also today to migrate to a other datastore with the option to make the disk thick. I got no error but still the disks are thin.

Can anyone confirm that i cannot be think on nfs ?

[fransje1975]

I do not now exactly why it has to be thick (just started to work here 2 days ago and the wanted it to be the disk thick). It will try to find out why exactly tomorrow.

[admin]

NFS stores only support thin-provisioned disks, so you're out of luck if you don't have any alternative storage. The reason thay want to use thick-provisioned disks is most likely performance as I believe that pre-ESX4 under certain workloads thick-provisioned disks performed better than thin-provisioned, however VMware claim this difference has to all intents and purposes disappeared with the release of ESX4 so it should not really be a concern.

There's a whitepaper with good info on this here: http://www.vmware.com/pdf/vsp_4_thinprov_perf.pdf

And a KB with some more general info thin-provisioned disk here: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100541...

Alex

www.phdvirtual.com

[fransje1975]

Please check this

http://pubs.vmware.com/vi35u2/wwhelp/wwhimpl/common/html/wwhelp.htm?context=server_config&file=sc_ap...

Here is says that nfs supports also thick format. So it has to be a other problem . Or has this been changed in vsphere

[adrianych]

One reason as to why thick is preferred over thin is when you are already running on thin storage like the Dell Equallogic storage which can provide thin storage. Can be dangerous for thin on thin......

[Giulio]

If NFS supports only thin provisioned vmdk's, then when vsp_41_availability.pdf says that

- Fault tolerance requires thick vmdk's

- Fault tolerance is supported on NFS

it's leaving some detail out?

Becaue if FT is supported on NFS, and if FT requires thick, and if NFS only supports thin, then something is not clear.