6.0.1

Setting LUN Allocations
This topic provides general information about how to allocate LUNs when your ESXi works in conjunction
with SAN.
When you set LUN allocations, be aware of the following points:
Storage provisioning
To ensure that the ESXi system recognizes the LUNs at startup time,
provision all LUNs to the appropriate HBAs before you connect the SAN to
the ESXi system.
VMware recommends that you provision all LUNs to all ESXi HBAs at the
same time. HBA failover works only if all HBAs see the same LUNs.
For LUNs that will be shared among multiple hosts, make sure that LUN IDs
are consistent across all hosts. For example, LUN 5 should be mapped to host
1, host 2, and host 3 as LUN 5.
vMotion and VMware
DRS
When you use vCenter Server and vMotion or DRS, make sure that the LUNs
for the virtual machines are provisioned to all ESXi hosts. This provides the
most ability to move virtual machines.
Active-active compared
to active-passive arrays
When you use vMotion or DRS with an active-passive SAN storage device,
make sure that all ESXi systems have consistent paths to all storage
processors. Not doing so can cause path thrashing when a vMotion
migration occurs.
For active-passive storage arrays not listed in Storage/SAN Compatibility,
VMware does not support storage port failover. In those cases, you must
connect the server to the active port on the storage array. This conguration
ensures that the LUNs are presented to the ESXi host.
Setting Fibre Channel HBAs
Typically, FC HBAs that you use on your ESXi host work correctly with the default conguration seings.
You should follow the conguration guidelines provided by your storage array vendor. During FC HBA
setup, consider the following issues.
n
Do not mix FC HBAs from dierent vendors in a single host. Having dierent models of the same HBA
is supported, but a single LUN cannot be accessed through two dierent HBA types, only through the
same type.
n
Ensure that the rmware level on each HBA is the same.
n
Set the timeout value for detecting a failover. To ensure optimal performance, do not change the default
value.
n
ESXi supports 16 GB end-to-end Fibre Channel connectivity.
Installation and Setup Steps
This topic provides an overview of installation and setup steps that you need to follow when conguring
your SAN environment to work with ESXi.
Follow these steps to congure your ESXi SAN environment.
1 Design your SAN if it is not already congured. Most existing SANs require only minor modication to
work with ESXi.
2 Check that all SAN components meet requirements.
vSphere Storage
40 VMware, Inc.