couchspawnkillable: Cannot allocate memory about couchdb

[sergey-safarov]

Before the issue was used 170Mb of swap memory

[nickva]

I don't typically run CouchDB in a docker container so this all speculative advice.

A few things to try:

• Adjusting couchjs process setting, lower their number with https://docs.couchdb.org/en/stable/config/query-servers.html#query_server_config/os_process_limit. Make the hard limit say 75 and soft limit 25. The default is 100 I think.

• Try lowering max_dbs_open. The default is 500 so maybe try making it 400 or 300.

• When running in docker, Erlang VM doesn't always do a good job auto-detecting the CPU quotas so it would start a scheduler thread for each core on the host machine. So try lowering the number of schedulers artificially in vm.args with +S 4:4, for example to use only 4 schedulers. The number of schedulers should match your CPU quota.

• Erlang VM has more advanced memory management settings. There is one to use a max amount of heap, so if you have a way to test it out on a test cluster first, try something like:
  vm.args:

+MMscs 4096
+Musac false
+MMsco true

That sets the super-carrier to 4GB max. Again, I haven't tried running with those settings but someone reported some success with that: https://elixirforum.com/t/running-elixir-with-limited-heap-size/23633/13