Choosing NAS, SAN or iSCSI Storage

SAN was once among the most expensive of network storage technologies. Its primary advantage is that it allows a computer to see the remote storage as a local device. This has to do with how files are transferred. In a SAN system, the files are transferred on the block level, which is exactly how your computer transfers files from a local device. NAS, on the other hand, is regarded as remote storage by the device with which it communicates.
iSCSI allows SAN storage to be provided over an Ethernet network. In the past, this type of storage required a fiber network, which is more expensive. Today's iSCSI systems allow your server, computer or any other device to regard a remote file storage device as local to itself. This protocol allows for very fast data transfer. You may wish to go with iSCSI if you're transferring large amounts of multimedia information or if  you need a networked drive to function as quickly as if it was attached to the computer directly, such as for certain server applications.
NAS systems are network storage appliances that allow data to be transferred over the network, but the computer or other device to which they're being transferred recognizes that they're not directly attached to the device. The protocol is different and the transfer rates are usually a bit slower than they are with SAN. However, NAS devices have a significant price advantage over many SAN and iSCSI devices. This makes them attractive particularly to smaller businesses that simply need a reliable storage appliance and that need it to be accessible to anyone on the network.
NAS systems are also very popular in home applications. They make excellent media stores and can quickly provide a great deal more storage for a home network. In an office environment, the benefits are the same. For fast restorations of files and for complex network applications, iSCSI devices are generally the preferred routes, however, due to their tremendous transfer rates. Where cost is concerned, businesses sometimes choose NAS to save money and get many of the same benefits. Both of these technologies benefit from constantly improving performance and software applications designed to work with them.
There are technologies, such as NetServ, that allow both technologies to be used on the same network. This creates a great deal more flexibility for the network and allows the company to take advantage of the benefits of both types of systems.