DMP in the hypervisor provides multi-pathing to the guests. In the VMware environment, the storage presented to a guest is abstracted from the number of paths physically connecting the ESX server to the back-end storage. To the guest, everything looks like only a single path to each disk device, regardless of what underlying protection is available at the hypervisor. Therefore, installing DMP in the guest cannot provide multi-pathing functionality. However, in the hypervisor, DMP can see all of the paths and provides multi-pathing and I/O load balancing between them.

In a shared virtualized environment, a large number of applications run on the same infrastructure. A reliable and mission critical infrastructure requires that the storage remains available. Storage availability is even more critical in a virtualized environment than in the physical environment, because an outage impacts a much larger number of applications.

Multi-pathing is critical to ensure that the storage remains available. DMP provides multi-pathing and I/O load balancing between the virtual machines (VMs).

Most mission-critical servers are designed to reduce single points of failure. An VMware ESXi server is no exception to this. Due to the large number of virtual machines and applications that are typically hosted on a single server, hardware redundancy is critical. DMP for VMware provides seamless, out of the box management of storage arrays and storage, providing the resiliency necessary to provision mission-critical workloads on VMware.

To achieve storage availability using DMP, install DMP for VMware in the hypervisor.

See the Symantec Dynamic Multi-Pathing Installation Guide - VMware ESX.