Storage area networks

Discover the advantages and disadvantages of storage area networks (SANs).

SANs are a newer development in the disk and tape attachment business. They consolidate the storage of multiple, storage devices into a single set of centrally managed resources. To do so, they employ a combination of technologies, including hardware, software, and networking components. They support direct, high-speed data transfers between systems and storage devices in the following ways:

System to storage

This is the traditional model of interaction with storage devices. The advantage of a SAN in this case is that the same storage device may be accessed serially or concurrently by multiple systems.

System to system

A SAN may be used for high-speed, high-volume communications between systems.

Storage to storage

This SAN data movement capability enables data to be moved without system intervention, thereby freeing system processor cycles for other activities like application processing. Examples include a disk unit backing up its data to a tape device without system intervention or remote device mirroring across the SAN. This type of data transfer is not currently available on the system.

SANs provide many benefits in your System i® network, including the following:

Scalability

Storage is independent of the system itself, so you are not limited by the number of disks you can attach directly to the system.

Improved availability of applications

Storage is independent of applications and is accessible through alternative data paths.

Better application performance

Storage processing is moved from the systems onto a separate network.

Centralized and consolidated storage

Storage capacity can be connected to systems at a greater distance, and storage resources can be disconnected from individual hosts. The results can be lower overall costs through better use of the storage, lower management costs, increased flexibility, and increased control.

Data transfer for storage at remote sites

You can keep a remote copy of data for disaster protection.

Simplified centralized management

A single image of storage media simplifies management.