By default, Hazelcast is the core/backbone for clustering in PRPC v7.1.9 through v7.3. We have provided Hazelcast specific hotfixes across the above versions to our customers who are running clusters of more than 10 nodes in PRODUCTION and have seen performance issues specifically with Hazelcast.
Starting v7.3, we support both Hazelcast and Apache Ignite. Hazelcast is still the default implementation.
Since Hazelcast doesn't support encryption OOTB, we implemented Ignite so that we could support HIPAA. As of 7.3, we also support an optional client/server configuration in Ignite only when the number of nodes is greater than 6. In a C/S configuration, we have standalone Ignite servers with Pega nodes set up as clients.
The System Pulse will use whichever cluster technology is in use.
Got the response from PEGA and below is the response from them.
To answer your question about enabling hazelcast for 10 Nodes, please note that there are no such issues per se with the number of nodes in with hazelcast. In fact, you can even have 20, 25 50+ nodes in the cluster. However, if you do encounter any issues, please do not hesitate to submit a new SR, and we'll be more than happy to assist you with any issues you may encounter