@cemk You need to check your Graylog server.log and elasticsearch log file. There might be your elasticsearch having an issue to accepting messages and log files will give you the exact cause of it.
Do you have outgoing messages? Maybe you just need a bigger elastic cluster.
But an @makarands mentioned, check logs first.
After the IO and other performaces of your graylog and elastic servers.
After that, please check the graylog config file’s comments about processor numbers, and ring sizes. You missconfigured it. (This problem not connected)
the problem we are having, Process Buffer - Output Buffer Full
Is increasing the number of graylog nodes the solution?
Is there anything wrong with the settings I sent ?
Yes, but the buffers fulls because the elastic can’t adsorb as many messages as graylog tries to send.
As I mentioned, check the config file’s comments. You should use less processors in the config what you have. Input, process, and output 's sum should be less then 16. But it is not releated with your problem…
And the ring size should fit in your processors cache.
But it’s just my memory, check the config and the docs.
As I see you decrease the batch size. Check the docs, what it is. Maybe it makes clear everything.