vSphere Storage - ESXi 5.1 - Documentation - VMware

vSphere Storage
Figure 20-1. Multipathing and Failover with Fibre Channel
Host 1 Host 2
HBA2 HBA1 HBA3 HBA4
switch switch
SP1
storage array
SP2
Similarly, if SP1 fails or the links between SP1 and the switches breaks, SP2 takes over and provides the
connection between the switch and the storage device. This process is called SP failover. VMware ESXi supports
both HBA and SP failovers with its multipathing capability.
Host-Based Failover with iSCSI
When setting up your ESXi host for multipathing and failover, you can use multiple iSCSI HBAs or multiple
NICs depending on the type of iSCSI adapters on your host.
For information on different types of iSCSI adapters, see “iSCSI Initiators,” on page 73.
When you use multipathing, specific considerations apply.
n ESXi does not support multipathing when you combine an independent hardware adapter with software
iSCSI or dependent iSCSI adapters in the same host.
n Multipathing between software and dependent adapters within the same host is supported.
n On different hosts, you can mix both dependent and independent adapters.
The following illustration shows multipathing setups possible with different types of iSCSI initiators.
194 VMware, Inc.