What is the RDM in VMware?

What is the RDM in VMware?

What is raw device mapping (RDM)? Raw device mapping (RDM) enables disk access in a virtual machine (VM) in the VMware server virtualization environment and allows a storage logical unit number (LUN) to be connected directly to a VM from the storage area network (SAN).

How do I map a RDM disk in VMware?

When you have created the RDM pointer file, attach the RDM to a virtual machine using the vSphere Client:

1. Right click the virtual machine you want to add an RDM disk to.
2. Click Edit Settings.
3. Click Add.
4. Select Hard Disk.
5. Select Use an existing virtual disk.

How do I expand my RDM disk?

To safely expand the RDM:

1. Expand the RDM LUN from the SAN side.
2. Perform rescan on the ESX and verify the new LUN size is observed.
3. svMotion the RDM pointer files or recreate the RDM mapping with the following steps to update the mapped disk size:
4. Perform a re-scan from the guest operating system.

How do I set up RDM?

Adding an RDM to a VM Step 1: To add the disk to the VM, right-click on the VM and select Edit Settings. Step 2: From the Virtual Hardware tab (1), click on New raw disk and select the Add new RDM disk option (2). Step 3: The non-allocated LUN (or device) should be listed next.

How do I add RDM to 2 VMs?

Procedure

1. In the vSphere Client, select the newly created virtual machine, right-click and select Edit Settings.
2. Click the New device drop-down menu, select RDM Disk, and click Add.
3. Select the LUN that is used by the physical machine.
4. Select the datastore, which is also the location of the boot disk.

Can you vMotion a VM with physical RDM?

When vMotioning a virtual machine to another host, you experience these symptoms: The virtual machines with physical mode RDM fail to vMotion. Cannot vMotion the virtual machines, when the RDM pointer file is not visible from destination host. The virtual machine has one or more physical mode RDM volumes.