SAN - Storage Area Network

SAN was developed to further improve storage performance and functions as a high performance storage network that transfers data between servers and storage devices separate from the local area network. Because of their high degree of sophistication, management complexity and cost, SANs are typically implemented in larger organizations.

SAN storage generally uses a collection of disks networked together using a low-latency network, typically fiber-channel though iSCSI is another option. The server is also connected to the SAN using a suitable SAN HBA (high bandwidth adapter). The storage is presented to the server via the storage HBA as though it were a locally attached disk with disk-block-level read and write capability. SAN storage can provide a very high level of performance and/or a very high level of redundancy.

Typically, the performance provided by SAN is unnecessary when using a PostPath Server™. The PostPath Server's™ simplified storage architecture and overall efficiency in terms of disk access makes the complexity of implementing a SAN largely unnecessary. Similarly, very high levels of reliability can be achieved using DAS and appropriate redundant configurations under Linux. The kind of snapshotting technologies that Exchange™ requires are not necessary using the PostPath Server™.

Nonetheless, SAN can be an effective choice for customers who have standardized on that technology, or who have SAN capacity already available, or who want to share a pool of storage with other applications that may be more demanding in terms of storage performance, provided they do not mind paying the costs-of-purchase that the SAN sometimes entails.