You can use ESXi in conjunction with a storage area network (SAN), a specialized high-speed network that connects computer systems to high-performance storage subsystems. Using ESXi together with a SAN provides storage consolidation, improves reliability, and helps with disaster recovery.
To use ESXi effectively with a SAN, you must have a working knowledge of ESXi systems and SAN concepts. Also, when you set up ESXi hosts to use Internet SCSI (iSCSI) SAN storage systems, you must be aware of certain special considerations that exist.