Introduction to Storage with respect to Application Development

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What is NAS?

A NAS box is a dedicated storage server that includes a NAS head and disk drives that are attached to a network. The NAS head (aka NAS front end or NAS gateway) is the control electronics that interface the network and storage. A basic NAS may use just one head or share the internal storage across multiple heads to accommodate increased network bandwidth.

What is SAN?

SAN is created by using the Fibre Channel to link peripheral devices such as disk storage and tape libraries. Storage performance is enhanced using a fast interface (e.g., 2 Gbps or 4 Gbps Fibre Channel) (FC) that connects storage servers and storage devices through switches and hubs to form a fabric that supports both redundancy and high availability

What is LOFS

A LOFS file system is a virtual file system that provides an alternate path to an existing file system. When other file systems are mounted onto an LOFS file system, the original file system does not change. Its mainly used in Zones to share files at very High Speeds using local cables for maximum speeds as its all within the same ZONE.

In Simple Language

NAS and SAN both are storage systems in which NAS provides shared File System across different applications using Ethernet. SAN on the other hand contains Blocks of storage where each block provides data to NAS/LOFS to share the filesystem across different applications. It uses High Speed Fiber Optic to transmit data.

NAS_SAN

In the above figure, SAN uses single block of storage via FIBER OPTIC, to NAS and it gets shared by both the Apps using NFS protocol to access.

LOFS_SAN

In the above example an illustration was done on how LOFS were handled within Zones.

Note: This document was written just with respect to Application Development Prospective and doesn't talk much or more about Storage Architecture. As most developers always get confused with the terminology used with respect to Storage, thought it would be useful for them to understand what does they really mean.