Knowing NAS from SAN
Network-attached storage (NAS) is not just storage-area network (SAN) spelled
backwards. Though they are often confused and may be used in tandem, they
are very different technologies.
NAS devices are attached directly to a network and act as dedicated,
high- performance storage resources.
A SAN is a high-speed, special-purpose network or subnetwork that connects
different kinds of storage devices. SANs are separate from agency local-area
networks or wide-area networks and are used exclusively for moving data
efficiently among servers and storage devices. A SAN is usually deployed
near mainframes, but may also extend to remote locations for backup and
archival storage, using WAN technology.
Although NAS and SAN are different technologies, they can work together.
A NAS can attach through a SAN to the storage system. In addition, some
IT administrators put NAS behind a server, instead of out on the network,
to create a SAN-like environment.
Still, neither is likely to replace the other because they are targeted
at different applications. Although a NAS is great for sharing general files
among a small workgroup, most organizations would not store financial documents
or other sensitive data on a NAS device. This type of data protection is
usually only offered via a SAN is a glasshouse environment. In addition,
only SANs are equipped with the reliability and scalability to handle the
"database pounding" associated with transactional, heavy applications.