To work properly with a SAN, your ESXi host must meet several requirements.

  • Verify that your ESXi systems support the SAN storage hardware and firmware. For an up-to-date list, see VMware 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 local storage. If you have diskless servers that boot from iSCSI SAN, see General Recommendations for Boot from iSCSI SAN 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. With this parameter set up, the Windows VMs can better tolerate delayed I/O resulting from a path failover. For information, see Set Timeout on Windows Guest OS.