SAN Design: March 29, 2001 3:18 pm
53-0001575-01 BROCADE Technical Note Page: 10 of 31
2.5 TWO SWITCH FABRIC FOR MIRRORING AND DISASTER TOLERANCE
FIGURE 5. Extended Fabric Example
H
SW
D
H
SW
•Sample configuration showing only two hosts and two storage
devices, larger configurations can be deployed
•This example shows how data being used at the local site can be
mirrored at a remote site via an extended fabric link. Primary system
data is replicated at remote site where a backup failover system is
located. Primary system disk information is mirrored to remote site that
can be 10KM distance with standard FC components (Long Wave
Length GBICs). Extended distances (20 to 120 KM possible) using
optical extender devices or DWDM devices.
•Starting with Fabric OS version 2.1.1, optional software to support
extended fabric is available. This allows increase in buffer-to-buffer
credits on E-ports to allow for maximum performance on links extended
over long distances. This option recommended when extended beyond
40KM.
•Mirroring across the link is accomplished by use of host based
mirroring software or by storage based mirroring options.
•Note: this configuration does not show a highly available solution,
there are single points of failure -- it points out the concept of remotely
mirroring data for disaster tolerance; other more highly available
architected solutions are possible at both sites.
•Alternative designs are possible where both sites mirror to each
other; sites can also consist of multi-switch fabrics connected over an
extended link
D
10 KM
Local Site
Primary Compute Site
Remote Site
Activated when
primary site fails