Understanding and Designing Serviceguard Disaster Recovery Architectures

Figure 26 Extended Distance Cluster with Two Data Centers and DWDM

Node A

Network Switch Network Switch

Node B

Cluster

Heartbeat

Network and

Storage

Connections

Data

replication

is being

done with

MirrorDisk/UX

Maximum

distance

100 kilometers

Node C Node D

Storage Storage

Cluster Lock

Site 1 Site 2

FC Switch

Cluster Lock

FC Switch

DWDMDWDM

DWDM DWDM

Network Switch Network Switch

In the figure 27, the alternate paths for both networking and Fibre Channel are configured through

separate redundant pairs of DWDM boxes. Each Fibre Channel switch has one ISL connected to

each DWDM box. You can also use a single DWDM box in each data center.The DWDM boxes

must be internally redundant and have no SPOFs, and have at least two dark fiber links between

them, each routed geographically differently, and the redundant standby fiber feature is configured

for the DWDM boxes. This cluster is not allowed to contain more than four nodes with Serviceguard.

For EC RAC clusters, the number of nodes allowed and the maximum distance supported vary,

depending upon the HP UX revision and the volume manager being used (see Table 2 (page 51),

Table 3 (page 51) and Table 4 (page 53) for details). Note that you cannot use SONET instead

of DWDM in this configuration, as SONET is not supported with dual cluster lock disks.

Extended Distance Cluster on HP-UX 65