mirror of
https://github.com/1f349/dendrite.git
synced 2024-11-24 12:41:34 +00:00
102 lines
4.0 KiB
Markdown
102 lines
4.0 KiB
Markdown
---
|
|
title: Optimise your installation
|
|
parent: Administration
|
|
has_toc: true
|
|
nav_order: 5
|
|
permalink: /administration/optimisation
|
|
---
|
|
|
|
# Optimise your installation
|
|
|
|
Now that you have Dendrite running, the following tweaks will improve the reliability
|
|
and performance of your installation.
|
|
|
|
## PostgreSQL connection limit
|
|
|
|
A PostgreSQL database engine is configured to allow only a certain number of connections.
|
|
This is typically controlled by the `max_connections` and `superuser_reserved_connections`
|
|
configuration items in `postgresql.conf`. Once these limits are violated, **PostgreSQL will
|
|
immediately stop accepting new connections** until some of the existing connections are closed.
|
|
This is a common source of misconfiguration and requires particular care.
|
|
|
|
If your PostgreSQL `max_connections` is set to `100` and `superuser_reserved_connections` is
|
|
set to `3` then you have an effective connection limit of 97 database connections. It is
|
|
therefore important to ensure that Dendrite doesn't violate that limit, otherwise database
|
|
queries will unexpectedly fail and this will cause problems both within Dendrite and for users.
|
|
|
|
If you are also running other software that uses the same PostgreSQL database engine, then you
|
|
must also take into account that some connections will be already used by your other software
|
|
and therefore will not be available to Dendrite. Check the configuration of any other software
|
|
using the same database engine for their configured connection limits and adjust your calculations
|
|
accordingly.
|
|
|
|
Dendrite has a `max_open_conns` configuration item in each `database` block to control how many
|
|
connections it will open to the database.
|
|
|
|
**If you are using the `global` database pool** then you only need to configure the
|
|
`max_open_conns` setting once in the `global` section.
|
|
|
|
You may wish to raise the `max_connections` limit on your PostgreSQL server to accommodate
|
|
additional connections, in which case you should also update the `max_open_conns` in your
|
|
Dendrite configuration accordingly. However be aware that this is only advisable on particularly
|
|
powerful servers that can handle the concurrent load of additional queries running at one time.
|
|
|
|
## 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`:
|
|
|
|
```bash
|
|
$ ulimit -Hn
|
|
1048576
|
|
|
|
$ ulimit -Sn
|
|
1024
|
|
```
|
|
|
|
Increase the soft limit before starting Dendrite:
|
|
|
|
```bash
|
|
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:
|
|
|
|
```yaml
|
|
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.
|