switch RDM physical mode to virtual mode problem

[Ercole77]

Hello to all.

I have a VM win 2003 r2 ent sp2 composed by:

1 virtual disk OS

1 rdm pointing to a lun in physical compatibility mode for data

Now i'm in progress to test a backup solution with VCB and i need snaphoot capacity. The goal is to convert the rdm in virtual compatibility.

My question are:

1) I tried to power off the vm, edit settings, select the disk but i cant switch physical to virtual because in greyed out....why? what's the correct procedure?

2) is it possibile to return again in physical compatibility or is a "one shot process"???

Many many thanks and excuse bad english

[Ercole77]

Sorry searching well in the forum i find that the correct method may be detach the rdm and then retach it in virtual compatibility.

Is it safe???

After, can i revert it in physical again with the same procedure?

thanks

[fridge]

I am just starting to work with RDM and I tried this in my test environment. I had an RDM setup in physical compatibility mode with data on it. I was able to shut down the guest and switch it to virtual compatibility mode. However, to do this I had to remove the disk and select "Remove from virtual machine and delete files from disk" in the Removal Options when doing this. I then added the RDM back in and selected virtual compatibility.

I was able to then work with snapshots on the RDM without any problem. After some testing I was able to repeat the process and switch back to physical compatibility mode.

Note: While I was able to do this w/o any problems, it was in a test environment and only limited testing. I would suggest some testing in your environment if possible and making sure you have a good backup of your data prior to trying this on production data.

[tonyspen]

As for answering, Is it Safe?

Then the answer is Always Make sure you have a backup of both your data and VM. And I am talking about a completely seperate copy of each. i.e not VMWare Sanpshots.

Make sure you commit / delete ALL snapshots you have prior to switching from Virtual to Physical compatibility mode as it will revert all you data on the RDM back to the time you made your last VMware snapshot. This is not documented, not in the VMware Course, Testking etc, but IT WILL happen. I have placed a Premier support request 2 weeks ago to have them forward me the official documentation that states that you must delete / commit VMware Snapshot prior to switching to Physical Compatibility mode, but they can not find anything. I have aslo posted in the feature request forums to have the interface bring up a warning or give you an option to not revert.

To replicate this;

1. In a VM which has a Virtual Compatibility mode disk, Create a VMware snapshot

2. Create a test.txt file on the Virtual RDM disk (eg. D:)

3. Shutdown the VM and remove the RDM

4. Reconnect the RDM to the VM in physical compatibility mode

5. Restart the VM

6. Check the drive where you created the test.txt file. It won't be there indicating it has been reverted back to the time of the snapshot.

No warning messages are ever received and you can not ever get the data back unless you have a full backup.

This is particularly relevant if you have a virtual Exchange or SQL server where you will lose all mail / data since the last snapshot.

[CMCC]

When you remove the rdm lun from the VM, is the data deleted? or data in that lun is preserve?

Thanks in advance

[PhoenixHawk]

As always the correct answer is:

It is preserved, but BACKUP before doing anything. Check this KB: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=100659...

If you have a storage with snapshot option it might be a good idea to snap it on the storage. It´s faster then a doing a backup/restore of the files in case of a failure and the machine is offline anyway so you don´t have open files in the file system. Good for testing.