The typical benefits of using a SAN are a very high return on investment (ROI),
a reduction in the total cost of ownership (TCO) of computing capabilities, and
a pay-back period (PBP) of months rather than years. Here are some specific
ways you can expect a SAN to be beneficial:
Removes the distance limits of SCSI-connected disks: The maximum
length of a SCSI bus is around 25 meters. Fibre Channel SANs allow you
to connect your disks to your servers over much greater distances.
✓ Greater performance: Current Fibre Channel SANs allow connection
to disks at hundreds of megabytes per second; the near future will see
speeds in multiple gigabytes to terabytes per second.
✓ Increased disk utilization: SANs enable more than one server to access
the same physical disk, which lets you allocate the free space on those
disks more effectively.
✓ Higher availability to storage by use of multiple access paths: A SAN
allows for multiple physical connections to disks from a single or mul-
✓ Deferred disk procurement: That’s business-speak for not having to buy
disks as often as you used to before getting a SAN. Because you can use
disk space more effectively, no space goes to waste.
✓ Reduced data center rack/floor space: Because you don’t need to buy big
servers with room for lots of disks, you can buy fewer, smaller servers —
an arrangement that takes up less room.
✓ New disaster-recovery capabilities: This is a major benefit. SAN devices
can mirror the data on the disks to another location. This thorough
backup capability can make your data safe if a disaster occurs.
✓ Online recovery: By using online mirrors of your data in a SAN device,
or new continuous data protection solutions, you can instantly recover
your data if it becomes lost, damaged, or corrupted.
✓ Better staff utilization: SANs enable fewer people to manage much
✓ Reduction of management costs as a percentage of storage costs:
Because you need fewer people, your management costs go down.
✓ Improved overall availability: This is another big one. SAN storage is
much more reliable than internal, server-based disk storage. Things
break a lot less often.
✓ Reduction of servers: You won’t need as many file servers with a SAN.
And because SANs are so fast, even your existing servers run faster
when connected to the SAN. You get more out of your current servers
and don’t need to buy new ones as often.
✓ Improved network performance and fewer network upgrades: You can
back up all your data over the SAN (which is dedicated to that purpose)
rather than over the LAN (which has other duties). Since you use less
bandwidth on the LAN, you can get more out of it.
✓ Increased input/output (I/O) performance and bulk data movement:
Yup, SANs are fast. They move data much faster than do internal drives
or devices attached to the LAN. In high-performance computing envi-
ronments, for example, IB (Infiniband) storage-network technology can
move a single data stream at multiple gigabytes per second.
✓ Reduced/eliminated backup windows: A backup window is the time it
takes to back up all your data. When you do your backups over the SAN
instead of over the LAN, you can do them at any time, day or night. If
you use CDP (Continuous Data Protection) solutions over the SAN, you
can pretty much eliminate backup as a separate process (it just happens
all the time).
✓ Protected critical data: SAN storage devices use advanced technology
to ensure that your critical data remains safe and available.
✓ Nondisruptive scalability: Sounds impressive, doesn’t it? It means you
can add storage to a storage network at any time without affecting the
devices currently using the network.
✓ Easier development and testing of applications: By using SAN-based
mirror copies of production data, you can easily use actual production
data to test new applications while the original application stays online.
✓ Support for server clusters: Server clustering is a method of making two
individual servers look like one and guard each other’s back. If one of
them has a heart attack, the other one takes over automatically to keep
the applications running. Clusters require access to a shared disk drive;
a SAN makes this possible.
✓ Storage on demand: Because SAN disks are available to any server in
the storage network, free storage space can be allocated on demand to
any server that needs it, any time. Storage virtualization can simplify
storage provisioning across storage arrays from multiple vendors.
This is from book <Storage Area Networks For Dummies®>.