QuickSpecs

6
Choose the right SAN
infrastructure
Fibre channel SANs: for larger,
more demanding environments
SANs have traditionally been built on a fibre channel
infrastructure. Because the fibre channel protocol is
specifically designed for storage networks, it provides a
high level of performance and reliability between servers
and storage devices.
For environments where high performance and the highest
level of availability counts (i.e., in data centers), but also
when fully integrated SAN backup is required, fibre channel
SANs will remain the ideal choice over the coming years.
Benefit of a SAN:
• Improved availability of mission-critical applications
– Reduce scheduled and unscheduled downtime
– Increase application disaster tolerance
• Improved storage utilization
– Increase efficiency of valuable IT assets
– Gain economies of scale
• Improved availability of enterprise information
– Increase efficiency of IT systems
– Enable more efficient business processes
• More effective storage management
– Increase CONTROL of storage environment
– Enables enterprise wide management
• Foundation for disaster tolerance
– A SAN enables “always on” infrastructure
IP SANs: the technology for smaller
businesses
For smaller IT environments looking for an affordable
and simple SAN solution, IP SANs are ideal. They allow
you to share stored data over a low cost Ethernet
infrastructure using a protocol called iSCSI.
A 1 Gb/s Ethernet network will provide sufficient
bandwidth to connect several servers to a SAN storage
device (using either standard network interface cards
or optional TOE cards that offload network tasks from
servers with high CPU loads).
To enable data security and performance, it is
recommended that your IP SAN and LAN are kept
separate. In a typical small IT environment, this requires
just a single unmanaged switch—or you could even
connect your servers to the storage device directly.
Advantages of an IP SAN
• Get the benefits of shared storage for less. IP SANs have
vastly reduced infrastructure costs compared to fibre
channel SANs, so you can save up to 50 percent on
the total solution
• IP SANs allow you to extend the benefits of shared
storage to smaller departments and remote locations
A SAN makes it easy to increase availability
Today’s IT environments require increasingly high levels of availability at all times. SANs can offer 24x7 availability thanks to a fully redundant architecture.
The following elements are building blocks for increased SAN availability.
Server clustering
Configuring two or more servers in a cluster provides
the following advantages: a cluster distributes
processing requests evenly between servers in the
cluster (load balancing), and allows a recovery server
to take over the operations of a primary server should
a failure occur. Clustered servers need access to the
same data, which requires an external storage system.
A SAN is recommended as it provides multiple
storage connections and scalability to meet
changing needs.
Multi-pathing
The connection between server and networked storage
solution has several components—HBA/NIC, switch,
cables, array controller. If one breaks, your connection
will fail. Multi-pathing guards against this. With
redundant components, traffic can be swapped from
one component to the other should a failure occur.
Multi-pathing software like HP StorageWorks Secure
Path, Microsoft
®
MPIO or QLogic failover detects failed
connections and initiates automatic failover.
Data replication
Data replication enables access to data—even if your
entire storage system fails—by continuously copying it
to a remote secondary array (e.g., at a second remote
location).
While higher-end environments perform this directly
between two disk arrays, smaller environments are
more suited to replication between servers connected
to a SAN over an IP network. This enables one-to-one,
one-to-many and many-to-many replication, and data
is synchronized in incremental blocks to reduce
network traffic.
Servers
Storage
Servers
Storage
Servers
Storage