Converging SAN and LAN Infrastructure with Fibre Channel over Ethernet for Efficient, Cost-Effective Date Centers

Converging SAN and LAN Infrastructure with Fibre Channel over Ethernet for Efcient, Cost-Effective Data Centers Page 2
Evolving SAN Environments
Deployment of SANs using both the common connection
fabrics—Small Computer System Interface over IP (iSCSI) and
Fibre Channel—is increasing dramatically, and that growth is
expected to continue through the foreseeable future, as shown in
Figure 1. Growth in deployment of iSCSI-based SANs is especially
prevalent in medium-sized businesses, branch ofces, and new
installations, while Fibre Channel SANs remain the choice for
enterprise-scale deployments.
Although use of Ethernet-based storage with iSCSI is growing
quickly, most installed SANs today are Fibre Channel, and as IT
managers deploy new servers in data centers, they need to be
able to access the existing storage networks. FCoE lets them do
this inexpensively and easily.
A number of factors promote this growth. Remote replication
of SAN data enables disaster recovery and allows data to be
centrally managed but accessed from multiple sites on a local
basis. Point-in-time snapshots are also a widely used SAN
capability, allowing organizations to maintain backups and
audit trails that are helpful operationally and that also facilitate
regulatory compliance. SANs are also typically needed for live
migration of virtual machines for automatic failover and load
balancing between servers. SANs also enable storage resources
themselves to be virtualized, decoupling the data-storage entities
from the physical hardware used to store them.
In addition to advanced features, SANs provide increased
availability, which is increasingly important as more applications
throughout the enterprise come to depend upon access to stored
data. SANs also decrease the need for empty hard drive space on
individual servers to accommodate future growth. Instead, extra
storage space can readily be added as needed to a centralized
point by means of a SAN topology.
For the servers in the environment to take advantage of benets
like these, they must be connected to the SAN. With Fibre
Channel SANs, one or more host bus adapters (HBAs) must be
purchased for each server, which adds considerably to equipment
costs. For mission-critical applications (and often others), most
organizations provide redundant connectivity, driving costs even
higher. It is necessary with Fibre Channel SANs to operate
separate networks for the LAN and SAN environments, as shown
in Figure 2. These separate networks require added expense due
to requirements such as increased numbers of network interfaces,
additional cabling and switch ports, and more complex support
requirements. Those expenses become even greater as the
environment grows over time.
Figure 1. Deployments of Fibre Channel and iSCSI SAN systems
are expected to continue growing at least through 2011.
(Source: Worldwide Disk Storage Systems 2007–2011, Forecast
Update, IDC, No. 209490, December 2007)
2005 2006 2007 2008 2009 2010 2011
9000
7500
6000
4500
3000
1500
0
Fibre Channel iSCSI
SAN Growth: Fibre Channel and iSCSI Storage Systems (in Petabytes)
Figure 2. Today, most data centers use separate LAN and
SAN networks with separate switches and network adapters in
the server; for Fibre Channel SANs. This topology requires a
dedicated Fibre Channel infrastructure.
Ethernet
Switch
Fibre
Channel
SAN Switch
SANLAN
Ethernet Fibre Channel