Merging Two Stacks
You can join or merge two stacks to create one larger stack. However, the maximum number of nodes in an active topology is eight.
The operation performed when two stack segments are joined together depends on the following factors:
- Whether a slot number is duplicated
- Whether both stacks have master nodes
- The states of the nodes in each stack
If the nodes are configured with stacking enabled, one of the following occurs:
- If two segments are joined, both have operational masters, and at least one of the nodes in one of the stacks duplicates a slot number of a node in the other stack, the join is allowed. The link that has just connected the two stacks shows as Inhibited. This prevents accidental stack joins. In this condition, the nodes on the joined segment can still be reconfigured centrally for stacking.
- If two segments are joined, both have operational masters, and all nodes have assigned slot numbers that are unique in both stacks, the dual master situation is automatically resolved.
- If two segments are joined, there are no duplicate slot numbers, one of the segments has a master and a backup node, and the other segment does not have either a master or a backup node, the nodes in this segment are acquired by the master node. These nodes become standby nodes in the stack.
The nodes that are not configured for stacking do not attempt to join the active topology but join the stack anyway.
Any nodes enabled for stacking that are isolated between nodes (that are not enabled for stacking) attempt to form an isolated active topology.
If one of the nodes that is not configured for stacking is then configured for stacking and restarted, the behavior is as if two active stacks were joined.