What is SAN & NAS

When an enterprise class machine is procured from a vendor like HP, IBM or DELL, it doesn’t come with a hard disk to store your data. The hard disk that is shipped with the machine is primarily used for loading the operating system. The capacity of such a hard disk will be generally 72GB, which will be mirrored if procured that way. So where can the users store their data? It can be stored in two types of places, the SAN and the NAS.

Storage Area Network means the storage is a separate entity that is connected to the machine through a separate network. This network will be different from the LAN. The storage area will be connected to the machine using a Fiber channel which gives a considerable speed in transferring the data. SAN uses block storage access which gives better performance. Also the data stored in the SAN area is accessed by disk numbers and it’s the raw data. This type of storage can be used for database storage. The SAN allocated to one machine cannot be accessed by any other machine and is not suitable for sharing data between machines.

Network Attached Storage is where the storage is in a different location and data transfer happen through the LAN. The impact on the LAN will be high when the data is transferred to the NAS. The data placed on the NAS is accessed by filenames and byte offsets. The security and permission on the files are also handled by NAS itself. For this reason, the accessing of he files will be slower than SAN. NAS is ideal for sharing the data between two machines even if the machine is using different operating systems. This type of storage can be used for file share servers, database backups, emails storages etc ….