In preparation for configuring your SAN and setting up your ESXi system to use SAN storage, review the requirements and recommendations.
Make sure that the SAN storage hardware and firmware combinations you use are supported in conjunction with ESXi systems. For an up-to-date list, see the vSphere Compatibility Guide.
Configure your system to have only one VMFS volume per LUN.
Unless you are using diskless servers, do not set up the diagnostic partition on a SAN LUN.
In the case of diskless servers that boot from a SAN, a shared diagnostic partition is appropriate.
Use RDMs to access raw disks. For information, see Raw Device Mapping.
For multipathing to work properly, each LUN must present the same LUN ID number to all ESXi hosts.
Make sure the storage device driver specifies a large enough queue. You can set the queue depth for the physical HBA during system setup. For information on changing queue depth for HBAs and virtual machines, see the vSphere Troubleshooting documentation.
On virtual machines running Microsoft Windows, increase the value of the SCSI TimeoutValue parameter to 60. This increase allows Windows to better tolerate delayed I/O resulting from path failover. For information, see Set Timeout on Windows Guest OS.