vSphere Storage - ESXi 5.1 - Documentation - VMware

Booting ESXi from Fibre Channel SAN 7
When you set up your host to boot from a SAN, your host's boot image is stored on one or more LUNs in the
SAN storage system. When the host starts, it boots from the LUN on the SAN rather than from its local disk.
ESXi supports booting through a Fibre Channel host bus adapter (HBA) or a Fibre Channel over Ethernet
(FCoE) converged network adapter (CNA).
This chapter includes the following topics:
n “Boot from SAN Benefits,” on page 57
n “Boot from Fibre Channel SAN Requirements and Considerations,” on page 58
n “Getting Ready for Boot from SAN,” on page 58
n “Configure Emulex HBA to Boot from SAN,” on page 60
n “Configure QLogic HBA to Boot from SAN,” on page 61
Boot from SAN Benefits
Boot from SAN can provide numerous benefits to your environment. However, in certain cases, you should
not use boot from SAN for ESXi hosts. Before you set up your system for boot from SAN, decide whether it is
appropriate for your environment.
CAUTION When you use boot from SAN with multiple ESXi hosts, each host must have its own boot LUN. If
you configure multiple hosts to share the same boot LUN, ESXi image corruption is likely to occur.
If you use boot from SAN, the benefits for your environment will include the following:
n Cheaper servers. Servers can be more dense and run cooler without internal storage.
n Easier server replacement. You can replace servers and have the new server point to the old boot location.
n Less wasted space. Servers without local disks often take up less space.
n Easier backup processes. You can backup the system boot images in the SAN as part of the overall SAN
backup procedures. Also, you can use advanced array features such as snapshots on the boot image.
n Improved management. Creating and managing the operating system image is easier and more efficient.
n Better reliability. You can access the boot disk through multiple paths, which protects the disk from being
a single point of failure.
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