You must meet several requirements for your ESXi host to work properly with a SAN.

  • Verify that your SAN storage hardware and firmware combinations are supported in conjunction with ESXi systems. For an up-to-date list, see vSphere Compatibility Guide.

  • Configure your system to have only one VMFS datastore for each LUN.

  • Unless you are using diskless servers, set up a diagnostic partition on a local storage. If you have diskless servers that boot from iSCSI SAN, see General Boot from iSCSI SAN Recommendations for information about diagnostic partitions with iSCSI.

  • Use RDMs for access to any raw disk. For information, see Raw Device Mapping.

  • Set the SCSI controller driver in the guest operating system to a large enough queue. For information on changing queue depth for iSCSI adapters and virtual machines, see vSphere Troubleshooting.

  • On virtual machines running Microsoft Windows, increase the value of the SCSI TimeoutValue parameter to allow Windows to better tolerate delayed I/O resulting from path failover. For information, see Set Timeout on Windows Guest OS.