Knowledge Base

The following restrictions apply to booting from SAN:

• You must have ESX Server 2.5 or 2.5.x.
  
  
• You must have installed ESX Server in boot-from-SAN mode.
  
  
• The HBA used for the boot LUN must not be dedicated to the VMkernel.
  
  
• The boot LUN must be visible from the lowest-numbered HBA that has any visible LUNs.
  
  
• The boot LUN must be visible from the lowest-numbered storage processor (attached to that HBA) that has any visible LUNs.
  
  
• The boot LUN must be the lowest-numbered LUN attached to that storage processor.
  
  
• If the storage array uses active-passive path configuration, the lowest-numbered path to the boot LUN must be the active path.
  
  
• LUNs must be masked so that each ESX Server machine sees only its own boot LUN.
  
  
• The HBA that controls the boot LUN must be a QLogic HBA; currently only the 23xx series is supported.
  
  
• The storage array must be one that is compatible (CLARiiON, FAStT, MSA, or Symmetrix, for example) as described in the VMware SAN Compatibility Guide (http://www.vmware.com/pdf/esx_SAN_guide.pdf).
  
  
• SAN connections must be via switch fabric; boot-from-SAN does not support Direct Connect or Fibre Channel arbitrated loop connections.
  
  
• Boot-from-SAN  is not supported for MSCS. The VM boot disk must be on local disk.
  
  
• Raw Device Mapping is not supported in conjunction with the boot-from-SAN feature.
  
  
• The HBA BIOS must be enabled and correctly configured to access the boot LUN.
  
  
• If you are running an IBM Blade Server, you must disable IDE drives on the blades.
  
  

More information on SAN configuration is available at http://www.vmware.com/pdf/esx25_san_cfg.pdf.

To read about how you can avoid losing data when installing in boot from SAN mode, see http://kb.vmware.com/kb/1540.