vsphere-esxi-vcenter-server-55-storage-guide

vSphere StorageSetting LUN AllocationsThis topic provides general information about how to allocate LUNs when your ESXi works in conjunctionwith SAN.When you set LUN allocations, be aware of the following points:Storage provisioningTo ensure that the ESXi system recognizes the LUNs at startup time,provision all LUNs to the appropriate HBAs before you connect the SAN tothe ESXi system.VMware recommends that you provision all LUNs to all ESXi HBAs at thesame 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 IDsare consistent across all hosts. For example, LUN 5 should be mapped to host1, host 2, and host 3 as LUN 5.vMotion and VMwareDRSActive-active comparedto active-passive arraysWhen you use vCenter Server and vMotion or DRS, make sure that the LUNsfor the virtual machines are provisioned to all ESXi hosts. This provides themost ability to move virtual machines.When you use vMotion or DRS with an active-passive SAN storage device,make sure that all ESXi systems have consistent paths to all storageprocessors. Not doing so can cause path thrashing when a vMotionmigration occurs.For active-passive storage arrays not listed in Storage/SAN Compatibility,VMware does not support storage port failover. In those cases, you mustconnect the server to the active port on the storage array. This configurationensures that the LUNs are presented to the ESXi host.Setting Fibre Channel HBAsTypically, FC HBAs that you use on your ESXi host work correctly with the default configuration settings.You should follow the configuration guidelines provided by your storage array vendor. During FC HBAsetup, consider the following issues.• Do not mix FC HBAs from different vendors in a single host. Having different models of the same HBAis supported, but a single LUN cannot be accessed through two different HBA types, only through thesame type.• Ensure that the firmware level on each HBA is the same.• Set the timeout value for detecting a failover. To ensure optimal performance, do not change the defaultvalue.• ESXi supports 16GB FC HBAs, but there is no support for full end-to-end 16GB connectivity from thehost to array. If you use 16GB FC HBAs running at 16GB, to get full bandwidth, create at lease two 8GBconnections from the switch to the storage array.Installation and Setup StepsThis topic provides an overview of installation and setup steps that you need to follow when configuringyour SAN environment to work with ESXi.Follow these steps to configure your ESXi SAN environment.1 Design your SAN if it is not already configured. Most existing SANs require only minor modification towork with ESXi.40 VMware, Inc.