Q-Logic 8100 SERIES 用户手册

8–Configuring FCoE in a Linux Environment

Boot-from-SAN

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For legacy servers, the most common boot method was to boot from a 
direct-attached disk. When booting from direct-attached disk, the server 
BIOS/UEFI locates the SCSI/IDE adapter BIOS, which contains instructions that 
enable the server to determine which of its internal direct-attach disks is the boot 
device. This boot method is called local boot. Local boot is not fault tolerant, nor 
does it allow centralized management of operating system images for rapid 
deployment scenarios and disaster recovery options. While many modern servers 
provide high-availability local disk configurations through server-based RAID 
controllers, other issues with local boot are paving the way for alternative boot 
methods.

The boot-from-SAN method places the boot device on the SAN—not locally on 
the server, as with direct-attached disks. This boot device is a LUN that resides on 
a Fibre Channel storage array device. The server communicates with the storage 
array on the SAN through a Fibre Channel adapter or a Converged Network 
Adapter. The adapter boot code (BIOS or UEFI) contains the instructions that 
enable the server to find the boot disk on the SAN.