Datasheet

6
Technology Overview
Xsan
High-performance, concurrent file sharing
Unlike NAS or DAS systems, which use network file-sharing protocols to deliver stored
data to clients, a SAN typically uses a high-speed Fibre Channel interconnect. SCSI data
and commands are sent across the SAN over high-speed Fibre Channel protocols for
faster file access and more efficient sharing. This allows many users in a workflow to
work with the same data at the same time, facilitating collaboration and increasing
productivity.
Network-based storage management
By consolidating data into one shared volume, you can utilize all available storage
resources more efficiently—and with greater flexibility. Storage devices can be
connected using a Fibre Channel switch to any computer or server on the SAN.
Centralized storage also streamlines management and makes it easier to control
user access.
Eliminating single points of failure
Because a SAN file system gives multiple servers access to shared storage, you can
eliminate single points of failure. For example, if one of the servers fails, another server
can take over its job and continue to serve the data to clients on the network.
Flexible SAN topology
With a SAN file system, such as Xsan, it’s easy to expand the capacity of your SAN as
storage needs grow. Simply add more Xserve RAID systems, and you can expand exist
-
ing volumes—or create new ones—that can be shared among the attached servers.
To increase the available bandwidth or processing power to your network services,
you can add more servers running the Xsan file system. These new systems can
have immediate block-level access to the same storage volumes and host network
services, such as web serving, file sharing, or media streaming, to additional network
or Internet clients.
Why a SAN file system?
Storage devices on the SAN appear as Logical
Unit Numbers, or LUNs. A LUN may be a disk,
a RAID set, or a slice of a RAID set. Using a
SAN file system, a SAN can aggregate LUNs
into a single volume, permitting simultane-
ous access to the same data from multiple
systems, while maximizing resource utilization
and scalability.
A SAN by itself—without a SAN file system—
must assign, or “provision,” each LUN to an
individual server or computer for its exclusive
use. This effectively separates data into “silos,”
stopping short of the collaboration benefits
of a SAN, as well as many of the management
and scalability benefits.
Ethernet LAN
SAN volume
Volume scales
dynamically as
you add storage
devices.
Performance scales
as you add servers.
Client systems
SAN File System Scalability