This is a general overview of the steps needed to install an OS as boot from SAN.  You should consult your SAN and HBA configuration for your specific configuration requirements.  Not all storage arrays support boot from SAN, please check with your vendor.

Assumptions / Requirements

1)      The Boot LUN must be assigned as LUN 0 to the HBA.

2)      The HBA must be configured as Point-to-Point only

3)      The HBA supports Boot from SAN

4)      The Fiber Channel Switch supports Boot from SAN.

5)      The LUN assigned as the boot device (LUN 0) is only accessible via one HBA port.

6)      Single HBA is used to boot (No Multi-Pathing / Load Balancing is in use until after the OS is installed, see Multi-Pathing / Load Balancing Boot configuration later in document)

7)      Some storage vendors do not support applications and their data installed onto the Boot from SAN disk.

a.       The boot from SAN disk should only contain the OS and basic support applications.

b.      Production applications like SQL Server, Exchange, etc. should have all components installed to separate SAN disks.

Single Path Boot from SAN Configuration

The following example uses QLogic HBA’s, if you are using Emulex adjust accordingly.

Qlogic HBA Configuration

1)      Reboot the computer and Press CTRL-Q to enter the Fast!UTIL utility

2)      Enable the BIOS

a.       Configuration Settings…Host Adapter Settings

b.      Change: Host Adapter BIOS to “Enable”

3)      Change the Selectable Boot Settings

a.       Choose Configuration Settings…Selectable Boot Devices

b.      Set the ‘Selectable Boot Device’ option to ‘Enabled’

c.       Select ‘Current Boot Node Name’

d.      Select the HBA (WWPN) from the list

e.       Select the LUN Number to boot from.

f.        Escape and Save changes

4)      Insert Bootable Windows CD or Floppy and complete OS installation as needed.

Multi-Pathing / Load Balancing Boot Configuration

The following example uses QLogic HBA’s, if you are using Emulex adjust accordingly.

Assumptions / Requirements

1)      Currently booting from a single HBA port with LUN 0

2)      Familiar with and can properly configure appropriate Multi-Pathing / Load Balancing software.

Qlogic HBA Configuration

1)      Assign the same LUN as LUN 0 to the second HBA Port.

2)      Install HDLM or other multi-pathing software

a.       Configure as needed.

3)      Reboot Server and Press CTRL-Q to enter the Fast!UTIL utility

4)      Change the Selectable Boot Settings

b.      Choose Configuration Settings > Selectable Boot Devices

c.       Select ‘Current Boot Node Name’

d.      Select the SECOND HBA (WWPN) from the list

e.       Select the LUN Number to boot from.

f.        Escape and Save changes

More Information:
Qlogic KB articles 10332 & 10825