Understanding and Designing Serviceguard Disaster Recovery Architectures

Figure 6 Reliability of the Network is Paramount

Node 1

Node 2 Node 3 Node 4

Data Center A

Network uses single route

Data Center B

Node 1

Node 2 Node 3 Node 4

Data Center A Data Center B

Network uses redundant route

Router

Disaster Recovery Local Area Networking

Ethernet networks is used to connect nodes in a disaster recovery architecture within the following

guidelines:

• Each node is connected to redundant hubs and bridges using two Ethernet host adapters.

Bridges, repeaters, or other components that convert from copper to fiber cable may be used

to span longer distances.

• Redundant Ethernet links must be routed in the opposite directions, otherwise a data center

failure can cause a failure of both networks. Figure 7 shows one Ethernet link routed from

data center A, to B, to C. The other is routed from A, to C, to B. If both links were routed from

A, to C, to B, the failure of data center C would make it impossible for clients to connect to

data center B in the case of failover.

Disaster Recovery Architecture Guidelines 15