What is the difference between physical and virtual RDM?
What is the difference between physical and virtual RDM?
Virtual mode is more portable across storage hardware than physical mode, presenting the same behavior as a virtual disk file. You can use this mode for both Cluster-in-a-box and cluster-across-boxes. To expand the size of the RDM, see Expanding the size of a Raw Device Mapping (RDM) (1007021).
What is physical RDM?
RDM is basically a Mapping file acts as a proxy for a raw physical storage device placed in a VMFS volume. Virtual Machine can directly access the storage device using RDM and RDM contains metadata which controls the disk access to the physical device.
What is a virtual RDM?
Raw Device Mapping (RDM) is VMware’s virtualization technology that allows a virtual machine (VM) to access a logical unit number (LUN) directly.
How do I change RDM from physical to virtual?
Right-click the Node A virtual machine and click Edit Settings. Add the RDM to the virtual machine as a new disk and select virtual compatibility mode (the naming of this option depends on the Esxi/Vcenter version used).
Can you clone a VM with RDM?
VM snapshot functionality is available to RDM used in virtual compatibility mode. Irrespective of the compatibility mode, an RDM disk is a volume on the FlashArray. Therefore the steps for cloning a VM are the same for both modes.
Can you snapshot a VM with RDM?
Considerations and Limitations Cannot use snapshot feature with RDM in physical compatibility . Physical compatibility mode allows the virtual machine to manage its own, storage-based, snapshot or mirroring operations.
Can you vMotion a VM with physical RDM?
Physical mode RDM data can be migrated to VMDK disks only through cold migration. If you are attempting a Storage vMotion of a virtual mode RDM using the Advanced method, and the RDM pointer mapping file is already present in the target datastore, the Storage vMotion finishes quickly, but without moving the data.
How move VM to RDM?
To ensure that the RDM pointers files are not stored on a local datastore, validate the location of the destination datastore:
- Identify where the RDM pointer files are stored:
- Navigate to VM > Select Migrate > Change datastore.
- Click Advanced.
- Click Current Location.
- Select the destination datastore.
- Click OK.
Can we migrate VM with RDM?
Migrating virtual machines with RDMs can be performed in three ways: Warm migration (vMotion), with the virtual machine powered on. Cold migration, with the virtual machine powered off. Storage migration (Storage vMotion), with the virtual machine powered on.
How long should I keep a VM snapshot?
Do not use a single snapshot for more than 72 hours. The snapshot file continues to grow in size when it is retained for a longer period. This can cause the snapshot storage location to run out of space and impact the system performance.
How do I Change An RDM from virtual to physical mode?
Power on the virtual machine. Note: An RDM can also be changed from virtual compatibility mode to physical compatibility mode. To change from virtual to physical compatibility mode, ensure there are no snapshots and select physical compatibility mode when completing step 6. Note: If RDMs are bigger than 2TB you must use vSphere Web Client.
What is the difference between RDM and virtual disk files?
In the physical compatibility mode, the RDM offers direct access to the SCSI device for those applications that require lower-level control. An RDM provides a number of benefits, but it should not be used in every situation. In general, virtual disk files are preferable to RDMs for manageability.
What is physical compatibility mode in RDM?
Physical mode also allows virtual-to-physical clustering for cost-effective high availability. Virtual Machine Snapshots are not available when the RDM is used in physical compatibility mode. You can use this mode for Physical-to-virtual clustering and cluster-across-boxes.
What is the difference between physical and virtual compatibility mode?
1. Virtual compatibility mode allows an RDM to act exactly like a virtual disk file, including the use of snapshots. 2. Physical compatibility mode allows direct access of the SCSI device for those applications that need lower level control.
