Boot from SAN can provide numerous benefits to your ESXi environment. However, in certain cases, boot from SAN is not compatible with your hosts. Before you set up your system for boot from SAN, decide whether it is appropriate for your environment.
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 boot LUN, ESXi image corruption might occur.
If you use boot from SAN, the benefits for your environment include the following:
Cheaper servers. Servers can be more dense and run cooler without internal storage.
Easier server replacement. You can replace servers and have the new server point to the old boot location.
Less wasted space. Servers without local disks often take up less space.
Easier backup processes. You can back up 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.
Improved management. Creating and managing the operating system image is easier and more efficient.
Better reliability. You can access the boot disk through multiple paths, which protects the disk from being a single point of failure.