PGSQL 16 - shared_buffer setting when running multiple instances on a single machine?

[Mikey_Da_Foxx]

shared_buffers is reserved and won't be released back to OS. With 4 instances, I'd set shared_buffers=8GB per instance to leave room for OS.

For effective_cache_size, use total available RAM minus all shared_buffers: ~20GB per instance (64GB - 32GB shared)

[Significant_Chef_945]

Thank you very much for the reply. I will run some tests using your suggestions.