Even though Windows Server 2003 is a lot better at handling boot-from-SAN configurations than earlier versions of Windows, managing a boot-from-SAN system still requires some special knowledge. This is especially true when replacing a failed server or host bus adapter (HBA).
Dell Computer has three recommendations for making the job easier in a Fibre Channel SAN.
Don't change out the HBA with the server (unless absolutely necessary). The HBA contains critical information identifying the SAN port. The more of that information you can preserve, the faster and easier it is to make the switch from failed server to healthy server. If possible, unplug the HBA from the failed server and put it into the replacement. Then reconfigure the BIOS in the new server to boot from the HBA.
If the server or HBA is a different model than the previous one, make sure the operating system is reconfigured with the proper drivers. The system may do this automatically, but it will still need the driver CD for the replacement hardware.
If you have to replace the HBA with the same make and model, you will still need to update the access rights on the RAID ports because of the change in the World Wide Name (WWN) of the new HBA. The HBA must also be configured to boot from the correct LUN. A LUN (logical unit number) is a unique identifier used on a SCSI bus that enables it to differentiate between up to eight separate devices (each of which is a logical unit). Each LUN is a unique number that identifies a specific logical unit, which can be a user, a file or an application program.
About the author: Rick Cook specializes in writing about issues related to storage and storage management.
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