Networked Storage Basics

Almost since the beginning of desktop computing, the ability to share has been essential. Flash forward 30 years, and not only are computers networked, behold the pervasiveness of the internet to every workstation and laptop, but soon every computer will have shared storage. The simplest form of sharing would be networked attached storage (NAS), where you use built in networking protocols (TCP/IP, SAMBA, NFS, AppleTalk, etc.) to mount a remote volume over the internet or over a local area network (LAN) to a client system. You can now parcel files, using the file sharing aspects of the operating system.

A more robust system in the NAS space, uses an intelligent controller, or server (Mac OS X Server, NAS head, etc.) to deliver storage connectivity.

Companies like NetApp and BlueArc have mastered the front end of the storage array, and allow on the fly configuration, modeling, and allocation of storage resources as the needs of the enterprise change. Certain applications, like databases, require block level access to storage devices, as if they were directly attached to an individual computer. Application performance may suffer if the program is looking for block level access, but only sees NAS, however, in general, NAS is fast and is a completely viable storage platform.

Be it a NAS environment or a storage area network (SAN), most likely SAN is the storage subsystem architecture anyway. Currently there are three ways to attach a SAN to a workstation or workgroup:

Fibre Channel
Gigabit Ethernet, GbE (iSCSI)
IEEE 1394a or 1394b (FireWire)

Each methodology has is benefits and pitfalls, but all offer rugged access to shared storage resources. With a shared storage solution, the workstation can boot from the SAN, share files and applications (if the software licensing agreement allows it), and make the backup and restore aspect of data management easier.