System information

View Storage Device Paths
Use the vSphere Client to view which SATP and PSP the host uses for a specific storage device and the status
of all available paths for this storage device.
Procedure
1 Log in to the vSphere Client and select a server from the inventory panel.
2 Click the Configuration tab and click Storage in the Hardware panel.
3 Click Devices under View.
4 Click Manage Paths to open the Manage Paths dialog box.
Setting a Path Selection Policy
For each storage device, the ESX/ESXi host sets the path selection policy based on the claim rules defined in
the /etc/vmware/esx.conf file.
By default, VMware supports the following path selection policies. If you have a third-party PSP installed on
your host, its policy also appears on the list.
Fixed (VMware)
The host always uses the preferred path to the disk when that path is available.
If the host cannot access the disk through the preferred path, it tries the
alternative paths. The default policy for active-active storage devices is Fixed.
Most Recently Used
(VMware)
The host uses a path to the disk until the path becomes unavailable. When the
path becomes unavailable, the host selects one of the alternative paths. The host
does not revert back to the original path when that path becomes available
again. There is no preferred path setting with the MRU policy. MRU is the
default policy for active-passive storage devices and is required for those
devices.
Round Robin (VMware)
The host uses an automatic path selection algorithm rotating through all
available paths. This implements load balancing across all the available
physical paths.
Load balancing is the process of spreading server I/O requests across all
available host paths. The goal is to optimize performance in terms of
throughput (I/O per second, megabytes per second, or response times).
Table 6-4 summarizes how the behavior of host changes, depending on the type of array and the failover policy.
Table 6-4. Path Policy Effects
Policy/Controller Active-Active Active-Passive
Most Recently Used Administrator action is required to fail back
after path failure.
Administrator action is required to fail back
after path failure.
Fixed VMkernel resumes using the preferred path
when connectivity is restored.
VMkernel attempts to resume using the
preferred path. This can cause path thrashing
or failure when another SP now owns the
LUN.
Round Robin No fail back. Next path in round robin scheduling is
selected.
Fibre Channel SAN Configuration Guide
62 VMware, Inc.