SAN administrators customarily use specialized array-based software for backup, disaster recovery, data mining, forensics, and configuration testing.
Storage providers typically supply two types of advanced services for their LUNs: snapshotting and replication.
Snapshotting creates space with efficient copies of LUNs that share common blocks of data. In general, snapshotting is used locally on the same storage systems as the primary LUN for quick backups, application testing, forensics, or data mining.
Replication creates full copies of LUNs. Replicas are usually made to separate storage systems, possibly separate sites to protect against major outages that incapacitate or destroy an entire array or site.
When you use an ESXi system in conjunction with a SAN, you must decide whether array-based or host-based tools are more suitable for your particular situation.