This topic describes what storage area networks (SANs) are and
how they can be used to provide centralized storage. It discusses advantages
and disadvantages and links you to more detailed information.
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 servers and storage devices in the following
ways:
- Server 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 servers.
- Server to server. A SAN may be used for high-speed, high-volume
communications between servers.
- Storage to storage. This SAN data movement capability enables
data to be moved without server intervention, thereby freeing server processor
cycles for other activities like application processing. Examples include
a disk device backing up its data to a tape device without server intervention
or remote device mirroring across the SAN. This type of data transfer is not
currently available on the iSeries™ server.
SANs provide many benefits in your iSeries network, including the following:
- Scalability. Storage is independent of the server itself,
so you are not limited by the number of disks you can attach directly to the
server.
- 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 servers onto a separate network.
- Centralized and consolidated storage.Storage capacity can
be connected to servers 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.