RDM not compatibility with vCloud Director

Products

• VMware Cloud Director

Issue/Introduction

Raw Disk Mapping unsupported in vCloud director

Environment

VMware Cloud Director

Resolution

Below are the reasons why Cloud Director never supported RDMs

1. It gives direct access to VMs.
2. The RDM is not available for direct-attached block devices or certain RAID devices.
3. If you are using the RDM in physical compatibility mode, you cannot use a snapshot with the disk. Physical
   compatibility mode allows the virtual   machine to manage its own, storage-based, snapshot or mirroring operations.
   (Virtual machine snapshots are available for RDMs with virtual compatibility mode).
4. You cannot map to a disk partition. RDMs require the mapped device to be a whole LUN.
5. Virtual machine with a physical compatibility RDM cannot be cloned, made into a template, or migrated if the
   migration involves copying the disk.

   Maintenance Overhead:
1. Have to map numerous LUNs to all hosts for your WSFC. Host boot times or storage rescans can take a long time.
2. Moving WSFC needs to remap or create new LUNs.
3. Need to manage LUNS for clusters separately.
4. If you use vMotion to migrate virtual machines with RDMs, make sure to maintain consistent LUN IDs for RDMs across
   all participating ESXi hosts.
5. Additional configuration on ESX to mark the device as perennially reserved