Is there a correlation between datomic peer memory and datomic transactor memory?

Hi @petr! What do you mean by correlation?

The peers must follow the in-memory transaction stream for all databases they are connected to, which is up to the memory-index-max setting (on the tranactor(s)!)

But processes can make independent choices about total JVM, object cache, etc. so long as they work within that rule. This is partially described at https://docs.datomic.com/on-prem/capacity.html#peer-memory.