SAN Introduction

* SAN is the network between Storage devices & Host/servers, designed & implemented to provide pool of Storage resources mainly to fulfill the exponential need of storage backbone for small & medium offices, Mid-range & large Enterprises Using Fibre Channel or iSCSI Technologies.
* SAN provides block-orient I/O between the Server systems and the target storage systems, in comparison of NAS that gives File-oriented I/O.
* In comparison to DAS & NAS, SAN provides High availability of storage resources, more Secure & Reliable, Cost effective, reduced Downtime, secured Backup storage solutions.
* SAN is designed & implimented using either robust Fibre Channel Technology (FC SAN) or evergreen Internet Protocol Technology (iSCSI SAN). might be using both in near future.
* The SAN is often built on a dedicated network fabric that is separated from the LAN network to ensure the latency-sensitive block I/O SAN traffic does not interfere with the traffic on the LAN network.
* Even when iSCSI SAN runs over Ethernet technology, the SAN may still be separated from the LAN either physically, or logically via VLAN to ensure the security and the QoS on the SAN traffic.
* SAN storage devices are specifically designed as stand alone devices that can communicate with the Servers or hosts of different server vendors, Operating system vendors, Host adapter vendors, Switch vendors.
* SAN Architecture, accommodates DAS Implemented setups within its infrastructure & hence, DAS & SAN setups will co-exist in the same SAN infrastructure & also allows Enterprises to migrate from existing DAS setups to newer SAN setups & implementations.
* SAN Islands, implemented in different geographical locations can communicate using gateway devices such as FCIP based gateway, iFCP based gateway & iSCSI based gateway.