What are the disadvantages to booting off the SAN? We are looking at booting Unix (HP, Sun, IBM and Linux) and Intel servers off the SAN to help with disaster recovery solutions.
While not considered to be disadvantages to
booting off a SAN
, there are certainly some things you need to take into consideration to have a functioning environment for disaster recovery. These would include having the appropriate host software (BIOS, drivers, operating system), along with adapters and firmware that support booting off of the SAN. It's also important that your storage subsystem support and be configured to handle SAN booting. Some servers expect a boot device to be a specific drive number or LUN, for example LUN 0. In a SAN environment where you want to have unique boot disks for different servers, you need to have a mechanism in your storage subsystem or switch that can present a unique LUN to a host, yet have the host see this remapped LUN as LUN 0. This makes the different servers think that they are booting off of their unique LUN 0 when they are actually booting off of different LUNs. You will also want to make sure that your zones are set up for disaster recovery, using different servers if needed with different WWPN. Lastly, you need to make sure that storage LUN masking supports the different servers being used.