Availability - Brocade Communications Systems SilkWorm 12000 Design, Deployment And Management Manual

3
SilkWorm 12000 Based SAN Designs

Availability

Two logical switches reside in the SilkWorm 12000 chassis. As mentioned earlier, during CP card
failover, there is a slight disruption of I/O for both switches. Additionally, any environmental problem or
operator error that could take out the whole chassis would then disrupt both fabrics simultaneously.
Because of this, in extreme availability-sensitive environments, each core switch should be on a different
chassis.
One advantage of a dual fabric solution is the ability to perform maintenance on one fabric without
impacting the other fabric. If a SilkWorm 12000 is used as a core and is split across each of the dual
fabrics, it is no longer possible to do this. Another advantage to a dual fabric solution is the ability to run
one version of Fabric OS in one fabric and a different version in the other fabric. This also would not be
possible if a single SilkWorm 12000 were used as a core and split across each of the dual fabrics. For this
reason, high availability configurations should only support one fabric per chassis. Some designers may
opt for a two chassis and a two or four switch core for optimal availability and to avoid catastrophic
failures as shown in Figure 3-12.
SW0 SW0
SW1 SW1
3800 3800 3800 3800 3800
3800
Figure 3-12 Two SilkWorm 12000 (2 or 4 Logical Switches) Core
Publication Number 53-0000251-02 3-19