User guide

Technical white paper | HP Enterprise Virtual Array Storage and VMware vSphere 4.x and 5.x configuration best practices
11
The resulting topology should be similar to that presented in Figure 3, which shows a vSphere 4.x server attached to an
EVA4400 array through a redundant fabric.
Figure 3. Highly-available EVA/vSphere 4.x SAN topology
The benefits of this topology include the following:
• The topology provides increased fault tolerance, with protection against the failure of an HBA, a single fabric, or a
controller port or controller.
• As described earlier, it is a best practice to access the Vdisk through the managing (optimal) controller for read I/O. Thus,
in the event of an HBA failure, failover occurs at the HBA-level, allowing the Vdisk to remain on the same controller.
For this reason, HP highly recommends configuring each HBA port in the ESX server to access one or more ports on each
controller.
• Similarly, a controller failure only triggers a controller failover and does not cause an HBA failover, reducing system
recovery time in the event of a failure.
• A fabric failure does not trigger a controller failover or force the use of the proxy path.