Cyberfed27
Hot Shot
Hot Shot

Basically an RDM is a formatted LUN volume (windows, linux etc..) that already exists.

If you want to move that LUN away from a physical server and apply it to say a virtual machine while preserving the data on that LUN, then that's when a RDM comes into play.

You will need to apply the appropriate zoning or mapping on your SAN so that the physical VMware host can access the LUN (essentially removing its acces from a physical server and moving it to the vmHOST). The same way you present a lun to your vmHOSTs on your SAN.

From there you can add the disk to any VM as you would add a new disk to a VM in its properties, the difference is you select the RDM option instead.

This works great, remember you have a 2TB size limit on RDM's ( I think its 2TB 'officially')

Save yourself some headache and make sure the datastore where the VM lives has a block size large enough to support the RDM you are attaching.

This will be important for cloning and snapshot purposes.

That's all there is to it.

I recently moved a 1.5TB LUN attached to a physical host to a VM via RDM when the physical host died. I was able to preserver the entire volume and had no issues.

View solution in original post

Reply
0 Kudos