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SAN and NAS: An illustrated guide to distinguishing the storage types

Debating whether to go with SAN or NAS? Take a closer look at how the two network-based storage technologies compare based on function, usage, advantages and disadvantages.

Title SAN and NAS: An illustrated guide to distinguishing the storage types

SAN and NAS are established methods used to create networked storage. However, each approach has its own unique features and benefits, as well as drawbacks. 

A SAN connects servers to storage with a network hardware fabric, usually through switches, to give many servers easy access to the storage. For a server application or OS, there's little difference between accessing data in a SAN or DAS. Both provide block access to data. A SAN is mainly used for block I/O and is preferred for structured data, such as data in a relational database. SANs initially required Fibre Channel networking, but, today, they also support Ethernet -- usually iSCSI.

NAS is used for remote file serving. NAS devices access files with a protocol, such as SMB or NFS. A NAS device operates as a server with its own file system. It controls the file I/O and file sharing and provides centralized data management. NAS can handle structured data, but it's preferred for storage of unstructured data, such as files, email and images. NAS uses traditional Ethernet networking.

Check out our infographic for a big-picture look at how SAN and NAS compare.