vSphere Storage - ESXi 5.1 - Documentation - VMware
vSphere Storage - ESXi 5.1 - Documentation - VMware
vSphere Storage - ESXi 5.1 - Documentation - VMware
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Best Practices for iSCSI <strong>Storage</strong> 14<br />
When using <strong>ESXi</strong> with the iSCSI SAN, follow best practices that <strong>VMware</strong> offers to avoid problems.<br />
Check with your storage representative if your storage system supports <strong>Storage</strong> API - Array Integration<br />
hardware acceleration features. If it does, refer to your vendor documentation for information on how to enable<br />
hardware acceleration support on the storage system side. For more information, see Chapter 21, “<strong>Storage</strong><br />
Hardware Acceleration,” on page 215.<br />
This chapter includes the following topics:<br />
n “Preventing iSCSI SAN Problems,” on page 127<br />
n “Optimizing iSCSI SAN <strong>Storage</strong> Performance,” on page 128<br />
n “Checking Ethernet Switch Statistics,” on page 131<br />
n “iSCSI SAN Configuration Checklist,” on page 131<br />
Preventing iSCSI SAN Problems<br />
When using <strong>ESXi</strong> in conjunction with a SAN, you must follow specific guidelines to avoid SAN problems.<br />
You should observe these tips for avoiding problems with your SAN configuration:<br />
n Place only one VMFS datastore on each LUN. Multiple VMFS datastores on one LUN is not recommended.<br />
n Do not change the path policy the system sets for you unless you understand the implications of making<br />
such a change.<br />
n Document everything. Include information about configuration, access control, storage, switch, server<br />
and iSCSI HBA configuration, software and firmware versions, and storage cable plan.<br />
n Plan for failure:<br />
n Make several copies of your topology maps. For each element, consider what happens to your SAN<br />
if the element fails.<br />
n Cross off different links, switches, HBAs and other elements to ensure you did not miss a critical<br />
failure point in your design.<br />
n Ensure that the iSCSI HBAs are installed in the correct slots in the <strong>ESXi</strong> host, based on slot and bus speed.<br />
Balance PCI bus load among the available busses in the server.<br />
n Become familiar with the various monitor points in your storage network, at all visibility points, including<br />
<strong>ESXi</strong> performance charts, Ethernet switch statistics, and storage performance statistics.<br />
n Be cautious when changing IDs of the LUNs that have VMFS datastores being used by your host. If you<br />
change the ID, virtual machines running on the VMFS datastore will fail.<br />
<strong>VMware</strong>, Inc. 127