diff --git a/docs/installation/10_next_steps.md b/docs/installation/10_next_steps.md new file mode 100644 index 000000000..3110b5562 --- /dev/null +++ b/docs/installation/10_next_steps.md @@ -0,0 +1,71 @@ +--- +title: Next steps +parent: Installation +has_toc: true +nav_order: 10 +permalink: /installation/start/nextsteps +--- + +# Next steps + +Now that you have Dendrite running, the following tweaks will improve the reliability +of your installation. + +## File descriptor limit + +Most platforms have a limit on how many file descriptors a single process can open. All +connections made by Dendrite consume file descriptors — this includes database connections +and network requests to remote homeservers. When participating in large federated rooms +where Dendrite must talk to many remote servers, it is often very easy to exhaust default +limits which are quite low. + +We currently recommend setting the file descriptor limit to 65535 to avoid such +issues. Dendrite will log immediately after startup if the file descriptor limit is too low: + +``` +level=warning msg="IMPORTANT: Process file descriptor limit is currently 1024, it is recommended to raise the limit for Dendrite to at least 65535 to avoid issues" +``` + +UNIX systems have two limits: a hard limit and a soft limit. You can view the soft limit +by running `ulimit -Sn` and the hard limit with `ulimit -Hn`: + +``` +$ ulimit -Hn +1048576 + +$ ulimit -Sn +1024 +``` + +Increase the soft limit before starting Dendrite: + +``` +ulimit -Sn 65535 +``` + +The log line at startup should no longer appear if the limit is sufficient. + +If you are running under a systemd service, you can instead add `LimitNOFILE=65535` option +to the `[Service]` section of your service unit file. + +## DNS caching + +Dendrite has a built-in DNS cache which significantly reduces the load that Dendrite will +place on your DNS resolver. This may also speed up outbound federation. + +Consider enabling the DNS cache by modifying the `global` section of your configuration file: + +``` + dns_cache: + enabled: true + cache_size: 4096 + cache_lifetime: 600s +``` + +## Time synchronisation + +Matrix relies heavily on TLS which requires the system time to be correct. If the clock +drifts then you may find that federation no works reliably (or at all) and clients may +struggle to connect to your Dendrite server. + +Ensure that the time is synchronised on your system by enabling NTP sync.