Knowledge

• Configure LUN Masking
  LUN Masking is used to hide certain LUNs for the ESX hyper-visor. All LUNs presented to the OS are under normal circumstances visible (assuming the LUNs are presented on the storage array). When installing ESX on a LUN you want to be sure you only see the partition you want to install ESX on, otherwise you risk overwriting valuable VMFS partition with VM’s. Hiding LUNs during installation is typically done on you storage array. To hide LUNs on ESX (not applicable during install):
  
  LUN masking has been changed since the ESX 3.x version. A new command is used:
  

  esxcli corestorage claimrules convert

  This new command allows you to (un)hide luns and the convert the previous LUN masking used in pre ESX 4 servers to the new format. To add a new LUN masking to need to hide the LUN on every available path to the storage controller! This means that the underlying command line needs to be executed for every path. The command to add a LUN is:
  

  esxcli corestorage claimrule add -r <claimrule_ID> -t <type> <required_option> -P <MASK_PATH> 

  This and more examples can be found here.
  
  More information on how to migrate you existing pre ESX 4 LUN masking configuration to the new format can be found here on page 94.
• Prepare SAN
  To prepare the FC SAN:
  • Connect the FC and Ethernet cables, referring to any cabling guide that applies to your setup. Check the FC switch wiring, if there is any.
  • Configure the storage array.
    • From the SAN storage array, make the ESX host visible to the SAN. (This is often referred to as creating an object.)
    • From the SAN storage array, set up the ESX host to have the WWPNs of the host’s FC adapters as port names or node names.
    • Create LUNs.
    • Assign LUNs.
    • Record the IP addresses of the FC switches and storage arrays.
    • Record the WWPN for each SP and host adapter involved.
      
      Caution! If you use scripted installation to install ESX in boot from SAN mode, you need to take special steps to avoid unintended data loss. See the Hide LUN section above!
  • Configure the HBA BIOS for boot from SAN.
  • Boot your ESX system from the ESX installation CD.
    
    
  To prepare the iSCSI SAN:
  
  Caution If you use scripted installation to install ESX when booting from a SAN, you must take special steps to avoid unintended data loss. See VMware knowledge base article 1540.

• • Connect network cables, referring to any cabling guide that applies to your setup.
  • Ensure IP connectivity between your storage system and server. This includes proper configuration of any routers or switches on your storage network. Storage systems must be able to ping the iSCSI HBAs in your ESX hosts.
  • Configure the storage system.
    • Create a volume (or LUN) on the storage system for ESX to boot from.
    • Configure the storage system so that the ESX system has access to the assigned LUN. This could involve updating ACLs with the IP addresses, iSCSI names, and the CHAP authentication parameter you use on the ESX system. On some storage systems, in addition to providing access information for the ESX host, you must also explicitly associate the assigned LUN with the host.
    • Ensure that the LUN is presented to the ESX system as LUN 0. The host can also boot from LUN 255. On storage systems that present volumes as multiple targets rather than multiple LUNs, the volumes are always presented as LUN 0.
    • Ensure that no other system has access to the configured LUN.
    • Record the iSCSI name and IP addresses of the targets assigned to the ESX host.
    • You must have this information to configure your iSCSI HBA.
• Configure FC or iSCSI HBA BIOS
  To boot from SAN you need fibre channel adaptors that support this option. When you presented a LUN you need to enter the BIOS of the adaptor during boot time of the server and configure the LUN you wish to boot from. During the installation of ESX this LUN is visible to install ESX onto. Specific instructions for a qLogic adaptor can be found here.  Instruction for the Emulex adaptor can be found here.
• Enable BIOS
  Instructions on how to enable the BIOS for Qlogic and Bootbios:
  
• Select Boot LUN
  If you are using an active/passive storage array, the selected SP must be on the preferred (active) path to the boot LUN. If you are not sure which SP is on the active path, use your storage array management software to find out. The target IDs are created by the BIOS and might change with each reboot.
  • Use the cursor keys to select the first entry in the list of storage processors.
  • Press Enter to open the Select Fibre Channel Device page.
  • Use the cursor keys to select the chosen SP and press Enter.
    • If the SP has only one LUN attached, it is selected as the boot LUN.
    • If the SP has more than one LUN attached, the Select LUN page opens. Use the arrow keys to position to the selected LUN and press Enter. If any remaining storage processors show in the list, position to those entries and press C to clear the data.
  • Press Esc twice to exit.
  • Press Enter to save the setting.
• Install VMware ESX/ESXi
  A detailed installation procedure can be found here.
• Determine boot LUN size in a given situation
  VMware recommends a partition of minimal 8 GB in size for the optional partitions. Best practice is to set the /var/log to a separate partition. More info on the best practices: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1009080
• FC or iSCSI HBA BIOS
  On dedicated Fibre channel and iSCSI cards a BIOS is available. Depending on the vendor of the card they function of the BIOS may vary, but mostly this BIOS is used to allow a server to boot from a SAN / NAS. More info in the VMware Storage guide.

Tools

• FC SAN Configuration Guide
• iSCSI SAN Configuration Guide
• Product Documentation