Difference Between SAN and NAS

SAN vs NAS

SAN (Storage Area Network) and NAS (Network Attached Storage) are two types of data storage systems who function, the storage and retrieval of data, are pretty much the same; but functions in pretty different manners. The primary difference between the two is the medium used in transmitting the data to and fro as NAS uses the network to transport the data while SAN doesn’t. With SAN, data typically passes through SCSI and fiber channels.

There is also a major difference between how SAN and NAS accesses the data stored in the media. While NAS deals with files and their properties, SAN deals with individual disk blocks. This is important as it is the server that maintains the file system of the SAN and switching to an incorrect file system would render the data useless. On the other hand, NAS has its own file system and it would store or retrieve files without giving the server access to the raw blocks on the drives. Because of this difference, it is possible to have multiple computers that run different operating systems to access a NAS but not a SAN. Since the NAS retrieves and stores the files on the drive, it provides another abstraction layer so that the accessing computer only needs to know the correct command for the operation.

Another key difference between the two appears when the need to back-up the contents of both arises. Backing up a NAS can be significantly faster than a SAN. This is because only the files need to be backed up in a NAS. With a SAN, all the individual blocks need to be backed up regardless of whether they content data or are simply blank.

Although some might think so, these two technologies are not mutually exclusive. There are hybrid systems that employ both SAN and NAS to provide flexibility and to take advantages of the strengths of both systems. NAS provides file level access while SAN provides access to the individual blocks on the drives.

Summary:

1. NAS works across the network while SAN doesn’t
2. NAS accesses data by file while SAN does by blocks
3. NAS manages its own file system while SAN does not
4. NAS can be accesses across multiple operating systems but not SAN
5. NAS backups are more efficient than SAN backups
6. NAS and SAN are not mutually exclusive

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