I put this same question on Oracle's community site but this site gets a lot of activity so I am posting here also. Apologies to anyone who is on both.
On Oracle 19c you cannot set the sessions parameter to more than 65536 so I believe that means that you can have at most 65536 sessions on a single node database.
If I had a two node RAC database could each node have 65536 sessions or are we limited to 65536 total for both nodes?
Bobby
Best Answer
Each Oracle instance in a RAC configuration maintains its own resources and sessions; you would be able to have up to 65536 sessions for each node in the cluster.
https://docs.oracle.com/database/121/RACAD/GUID-59DEC066-5743-4EDE-9A02-E8896005F658.htm#RACAD818