storage vmotion of RDM disks

[vincentc]

Hi,

I am trying to perform a storafe vmotion of several VM.

All of them have the OK disk as vmdk and the data disk as a Virtual RDM

I would like to move the vRDM to a thick vmdk but it moves only the pointer to the new store and does not create a new vmdsk as I would have expected.

I have tried with the 'Advanced' option too, to make sure that "thick" format is selected but it makes no difference.

Is there a way to 'convert' a vRDM to vmsk on the fly, or does it need to be done when the VM is shutdown?

Thanks

[AndreTheGiant]

See: http://kb.vmware.com/kb/1005241

You must use a cold migration

Andre

[vincentc]

Thanks Andre

I find the document quite confusing.

For Storage Vmotion it says that the virtual files are physically reallocated to a destination datastore.

I was under the impression that it could be achieved as long as the RDM were virtual and not physicall.

I have about 80 VM with numerous size vRDM disks which need to be moved to vmdk datastores and I will not be able to shutdown for such period of time.

Is there a workaround or another way to do this?

Thanks in advance

[stinklyonion]

thanks for this link, Andre. i have been looking for this information for some time now. i really got a lot of information especially in Cold Migration and Cloning which is what i really need.

[cho9045]

Vincentc,

I understand that it is possible in vSphere 4.x environment as described in the KB article. But it is not for VI3.5 environment.

So if you use VI3.5, I think, you should use cold migration as Andre mentioned.

QUOTE>>

For Virtual Infrastructure 3.5, Virtual Disks and Virtual and Physical Mode RDM pointer files can be relocated to the destination datastore but cannot be converted to thick-provisioned or thin-provisioned disks during migration. The RDM pointer files of the virtual machine remain as RDM pointer files when the process completes.

For vSphere 4.x, Virtual Disks and Virtual Mode RDM pointer files can be relocated to the destination datastore, and can be converted to thick-provisioned or thin-provisioned disks during migration as long as the destination is not an NFS datastore. Physical Mode RDM pointer files can be relocated to the destination datastore, but cannot be converted.

<<END OF QUOTE

Regards,

[timemachine]

hey vincemet,

there is a trick and it works at times....neverthless u can try it on one vm and if it clicks then do it for other vms as well.

use standalone converter and while selecting the source machine type select "physical machine" instea d of "vmware virtual machine" it will allow u to do the conversion witheout powring vms down. let me know if it clicks .

[vincentc]

Thanks Guys

As chi9045 mentionned, and it was my understanding too, the storage vmotion should work for my Virtual RDM as I am running ESX 4.

However only the pointers are moved, no conversion take place of the vRDM themselves. Not sure why it is not working.

For the standalone converter, I am not 100% sure it will work. Most of our vRDM are several hunderd of Gb. It will take some time to convert. Once the conversion is completed I will have to shutdown the 'live' VM and start the converted VM. I am a bit scared that all the changes on the 'live' VM that occured during the conversion will not be on the new rebooted converted VM. What are your thoughts?

Thanks

[timemachine]

Hi ,

In converter you get an option which says
synchronize changes made to sourcce after completion to destination.  all u need to do is put the tick mark next to it.

[FishFace69]

I had the same problem. 

Going straight to thick Format (Lazy or Eager Zeroed), would not work for me - the RDM pointer would move and the disk would remain as RDM

I found that the destination disk type must be set to thin.  No need to use advanced options.

Once the RDM has been hot converted to Thin, you can always migrate a second time if you want to use the Thick format.

Cheers

[TonyNguyen]

If you are using vCenter 5, you can do a on the fly conversion of an RDM to thin/thick RDM as long as the RDM is virtual.

Exact same steps as you performed, going into the advanced properties and selecting a different disk format. Same steps, just doesn't work on a ESXi4 host but works on an ESXi5. :smileyconfused:

Seems if you have 80 machines with RDM's it would be worthwhile to upgrade to ESX5i just for this purpose!

Do you have to do this live? An outage and a cold migration would be the least amount of pain.

However, the VMware Converter and synchronize changes should work. In the mean time, your old VM continues to run so you can roll back to it if you run into any issues. It'd be very time consuming to do it 80 times though, go for ESXi 5.

[TonyNguyen]

Hi Fish,

What version of ESX on the source and destination hosts? I don't think it worked when I did from 4 -> 5, thin or thick. 5 -> 5 worked like a champ.

[FishFace69]

My install was vCenter 5 managing ESXi 4.1 -> ESXi 4.1  build 721871.

[TonyNguyen]

Are you able to update to ESX5? The RDM to VMDK process will be so much more easier!

[FishFace69]

So I found no need to upgrade to ESX 5 immediately just to get this feature.  4.1 will convert an RDM on the fly provided you select the thin format for the destination.  The documentation link says it can do it but is vague, so I'm sure catches a lot of peole out.

We will upgrade this customer to ESXi 5 eventually, but no need to go through a major exercise when the feature is already available.  I had also previously tried using advanced features to migrate the RDM, making sure I was migrating the VMX and other disks also to a fresh VMFS volume at the same time and selecting both Thick types, and the conversion would still fail.   As soon as I tried to go to a thin destination type, everything just worked (either using advanced or the basic interfaces).

I was running vCenter 5 - but would like to think the option would work under vCenter 2.5 also

Hope this helps someone else in need of a quick fix. 

Cheers

.