VMware has the ability to pass through from shared storage the raw settings of a LUN to a single VM. This Raw Device Mapping (RDM) is achieved using a proxy file inside of a VMFS volume. The benefits of this include being able to send disk commands to the storage, and support for clustering technologies. In the Veeam world this has stopped backups from working as Veeam has traditionally accessed VMware snapshots to perform backups.
With the addition of physical agents, centrally managed through either the Veeam console or through Veeam Availability Console, these VM’s can now be protected, providing cluster aware backups on RDMs, inside of the virtual world.
Before we dive into protecting RDMs, lets take a look at what they are, how they are different, and some competing technologies.
For block storage presented to VMware, there are four major ways to use the storage. RDMs, independent disks, vmdks, and VVols. Continue reading “RDMs, Clusters, and Veeam”