We sometimes want more than 2 nodes in a peer to peer (master-master) replication. In fact sometimes we only have such type of environment with number of nodes exceeding two. The reason for this type of configuration may be the ability to have more flexibility in pointing different applications to different nodes, ensuring that even if one node goes down, there still exists a peer to peer replication, etc. The question sometimes arises as to whether there is any limit prescribed by Shareplex as to how many nodes can exist in peer to peer replication.
Shareplex does not prescribe a limit on how many nodes can exist in a peer-to-peer replication environment. There are some limitations that one needs to be aware of:
1. If using named queues, then a maximum of 25 named queues can be configured per sp_cop. A combination of number of nodes and number of named queues can quickly exceed this limitation.
2. The more number of nodes involved in a peer-to-peer environment, the more management may be required in terms of configuration of conflict resolution routines, resync activity to correct the out of sync conditions from time to time, application of Shareplex patches and upgrades, resolving issues on so many target nodes that may have been caused by something originating from source, among others.
3. There could be resource issues to deal with. One may have to deal with network traffic issues because of the data throughput caused by Shareplex when sending data from one node to the other nodes. The increased # of named queues because of so many nodes may require more shared memory.
There could be other factors involved which can best be investigated by the Processional Services arm of Quest. Such expertise lies in the realm of Professional Services and Support would be happy to provide their contact information if needed.