ServerNet Cluster Manual

ServerNet Cluster Description
ServerNet Cluster Manual—520575-003
1-7
Three Network Topologies Supported
Tri-Star Topology
The tri-star topology, introduced with the G06.14 RVU, supports from 2 to 24 nodes
and uses up to six cluster switches—three for the X fabric and three for the Y fabric.
The three cluster switches on each fabric can have a position ID of 1, 2, or 3.
Consequently, the cluster switches on the X fabric are named X1, X2, and X3 and the
cluster switches on the Y fabric are named Y1, Y2, and Y3.
The first cluster switch on a fabric (X1 or Y1) supports ServerNet nodes 1 through 8,
the second cluster switch on the same fabric (X2 or Y2) supports ServerNet nodes 9
through 16, and the third cluster switch on the same fabric (X3 or Y3) supports
ServerNet Nodes 17 through 24.
Figure 1-4 shows both fabrics of a 24-node ServerNet cluster connected in a tri-star
topology.
Subsets of a Topology
You can build your cluster as a subset of either the split-star or the tri-star topology.
For example, even though a tri-star topology can contain three cluster switches per
fabric, you can build a tri-star topology that uses only one or two switches per fabric.
The advantage of a topology subset is that it allows you to grow the cluster quickly
online as your applications grow.
Table 1-1 lists the valid subsets for each topology. A subset of a topology must meet all
the requirements for the topology shown in Table 2-8 on page 2-23.
Table 1-1. Topology Subsets
Topology
Full
Topology
or Subset
Cluster
Switches
Per Fabric Using cluster switches . . .
Provides
ServerNet node
numbers . . .
Star Full 1 X1/Y1 1 through 8
Split-star Full 2 X1/Y1 and X2/Y2 1 through 16
Subset 1 X1/Y1 1 through 8
Subset 1 X2/Y2 9 through 16
Tri-star Full 3 X1/Y1, X2/Y2, and X3/Y3 1 through 24
Subset 2 X1/Y1 and X2/Y2 1 through 16
Subset 2 X1/Y1 and X3/Y3 1 through 8 and
17 through 24
Subset 2 X2/Y2 and X3/Y3 9 through 24
Subset 1 X1/Y1 1 through 8
Subset 1 X2/Y2 9 through 16
Subset 1 X3/Y3 17 through 24