SSR Cluster Network Requirements
A redundant cluster requires a redundant network. We require dual interface cards in each C Series Controller. Use the SRC group interfaces feature to bond the two interfaces to a single IP address.
We recommend that the network be a dedicated subnet with dual switches. This fully duplicates the network, and each C Series Controller in the cluster has at least two routes to all other C Series Controller, as shown in Figure 1.
The SSR database schema uses primary key lookups as often as possible during transaction processing, so the database cluster performance scales almost linearly based on the number of data nodes in the cluster.
Do not configure the subnet to be shared beyond the cluster C Series Controllers, because communications between nodes are not encrypted or shielded in any way. The only means of protecting transmissions within a cluster is to run your cluster on a protected network; do not interpose firewalls between any of the nodes.
Running the cluster on a private or protected network also increases efficiency because the cluster has exclusive use of all bandwidth between cluster nodes. This protects the cluster nodes from interference caused by transmissions between other devices on the network.
The SSR cluster requires Gigabit Ethernet between data nodes and the switch. Client nodes to the switch can use 100Base-T but Gigabit Ethernet is recommended. Network latency can severely degrade performance, as shown in Table 1, so we also recommend that all servers be close enough together that latency is always much less than 10 ms.
Table 1: Latency Between Servers and Its Effect on Performance
0 ms latency (LAN)
Baseline performance as designed
10 ms latency
Up to 40% performance loss
20 ms latency
Up to 60% performance loss
More than 20 ms latency