Scroll to navigation



synctl - Synapse server control interface


Start, stop or restart synapse server.

synctl {start|stop|restart} [configfile] [-w|--worker=WORKERCONFIG] [-a|--all-processes=WORKERCONFIGDIR]


synctl can be used to start, stop or restart Synapse server. The control operation can be done on all processes or a single worker process.


The value of action should be one of start, stop or restart.
Optional path of the configuration file to use. Default value is homeserver.yaml. The configuration file must exist for the operation to succeed.
Perform start, stop or restart operations on a single worker. Incompatible with -a|--all-processes. Value passed must be a valid worker´s configuration file.
Perform start, stop or restart operations on all the workers in the given directory and the main synapse process. Incompatible with -w|--worker. Value passed must be a directory containing valid work configuration files. All files ending with .yaml extension shall be considered as configuration files and all other files in the directory are ignored.


Configuration file may be generated as follows:

$ python -B -m -c config.yaml --generate-config --server-name=<server name>


Synapse´s architecture is quite RAM hungry currently - a lot of recent room data and metadata is deliberately cached in RAM in order to speed up common requests. This will be improved in future, but for now the easiest way to either reduce the RAM usage (at the risk of slowing things down) is to set the SYNAPSE_CACHE_FACTOR environment variable. Roughly speaking, a SYNAPSE_CACHE_FACTOR of 1.0 will max out at around 3-4GB of resident memory - this is what we currently run the on. The default setting is currently 0.1, which is probably around a ~700MB footprint. You can dial it down further to 0.02 if desired, which targets roughly ~512MB. Conversely you can dial it up if you need performance for lots of users and have a box with a lot of RAM.


This man page was written by Sunil Mohan Adapa <> for Debian GNU/Linux distribution.


synapse_port_db(1), hash_password(1), register_new_matrix_user(1)

February 2017