Elasticsearch + Debian 11 | tweak the server

Set ulimit -n: Edit /etc/profile and add ulimit -n 65535 Disable swapping by removing all swap lines from your fstab. As an alternative add the following line to your elasticsearch.yml: bootstrap.memory_lock: true Then test it using the famous Kibana (DevTools) Console: GET _nodes?filter_path=**.mlockall It should return true. Do not tune the java dns timeouts.

Linux | Too many open files

With systemd: /etc/systemd/system.conf DefaultLimitNOFILE=128000 You are a lucky admin who is NOT running systemd: /etc/security/limits.conf * soft nofile 128000 * hard nofile 128000 * hard nproc 128000 * soft nproc 128000 root soft nofile 128000 root hard nofile 128000 Check with # ulimit -n