Backing up independent disks and RDMs

VMware vSphere does not provide snapshots of independent disks or of Raw Device Mapping (RDM) disks in physical compatibility mode. Therefore, Agent for ESX(i) cannot back up such disks when the virtual machine is online or suspended.

When a virtual machine is online, the agent skips these disks and adds warnings to the log. You can avoid the warnings by excluding independent disks and RDMs in physical compatibility mode from the backup plan.

A suspended machine with independent disks or RDMs cannot be backed up at all. The backup will fail.

When a virtual machine is offline (powered off), Agent for ESX(i) can access the independent disks and RDMs in physical compatibility mode via ESX(i). Then, the agent can copy the information from them in a consistent state. As a result, the agent is able to back up all of the disks regardless of their mode.

The following table shows the role which the state of a virtual machine plays on whether Agent for ESX(i) can back up a disk. The table applies to all versions of ESX(i) supported by the agent.

VM disk modes

ESX(i) machine state

Online

Suspended

Offline

Basic virtual

+

+

+

Independent persistent

+

Independent nonpersistent

+

RDM in physical compatibility mode

+

RDM in virtual compatibility mode
(basic virtual)

+

+

+

RDM in virtual compatibility mode
(independent persistent)

+

RDM in virtual compatibility mode
(independent nonpersistent)

+

If you want to back up independent disks and RDMs in physical compatibility mode, do one of the following: