Qlogic QConvergeConsole CLI 8100 Series, User Manual

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8–Configuring FCoE in a Linux Environment
Boot-from-SAN
FE0254601-00 A 8-29
Figure 8-11. Comparing NPIV Physical and Virtual Ports
Boot-from-SAN
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.