dendrite/docs/installation/1_planning.md

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Planning your installation	Installation	1	/installation/planning

Planning your installation

Modes

Dendrite consists of several components, each responsible for a different aspect of the Matrix protocol. Users can run Dendrite in one of two modes which dictate how these components are executed and communicate.

• Monolith mode runs all components in a single process. Components communicate through an internal NATS server with generally low overhead. This mode dramatically simplifies deployment complexity and offers the best balance between performance and resource usage for low-to-mid volume deployments.

• Polylith mode runs all components in isolated processes. Components communicate through an external NATS server and HTTP APIs, which incur considerable overhead. While this mode allows for more granular control of resources dedicated toward individual processes, given the additional communications overhead, it is only necessary for very large deployments.

Given our current state of development, we recommend monolith mode for all deployments.

Databases

Dendrite can run with either a PostgreSQL or a SQLite backend. There are considerable tradeoffs to consider:

• PostgreSQL: Needs to run separately to Dendrite, needs to be installed and configured separately and and will use more resources over all, but will be considerably faster than SQLite. PostgreSQL has much better write concurrency which will allow Dendrite to process more tasks in parallel. This will be necessary for federated deployments to perform adequately.

• SQLite: Built into Dendrite, therefore no separate database engine is necessary and is quite a bit easier to set up, but will be much slower than PostgreSQL in most cases. SQLite only allows a single writer on a database at a given time, which will significantly restrict Dendrite's ability to process multiple tasks in parallel.

At this time, we recommend the PostgreSQL database engine for all production deployments.

Requirements

Dendrite will run on Linux, macOS and Windows Server. It should also run fine on variants of BSD such as FreeBSD and OpenBSD. We have not tested Dendrite on AIX, Solaris, Plan 9 or z/OS — your mileage may vary with these platforms.

It is difficult to state explicitly the amount of CPU, RAM or disk space that a Dendrite installation will need, as this varies considerably based on a number of factors. In particular:

• The number of users using the server;
• The number of rooms that the server is joined to — federated rooms in particular will typically use more resources than rooms with only local users;
• The complexity of rooms that the server is joined to — rooms with more members coming and going will typically be of a much higher complexity.

Some tasks are more expensive than others, such as joining rooms over federation, running state resolution or sending messages into very large federated rooms with lots of remote users. Therefore you should plan accordingly and ensure that you have enough resources available to endure spikes in CPU or RAM usage, as these may be considerably higher than the idle resource usage.

At an absolute minimum, Dendrite will expect 1GB RAM. For a comfortable day-to-day deployment which can participate in federated rooms for a number of local users, be prepared to assign 2-4 CPU cores and 8GB RAM — more if your user count increases.

If you are running PostgreSQL on the same machine, allow extra headroom for this too, as the database engine will also have CPU and RAM requirements of its own. Running too many heavy services on the same machine may result in resource starvation and processes may end up being killed by the operating system if they try to use too much memory.

Dependencies

In order to install Dendrite, you will need to satisfy the following dependencies.

Go

At this time, Dendrite supports being built with Go 1.16 or later. We do not support building Dendrite with older versions of Go than this. If you are installing Go using a package manager, you should check (by running go version) that you are using a suitable version before you start.

PostgreSQL

If using the PostgreSQL database engine, you should install PostgreSQL 12 or later.

NATS Server

Monolith deployments come with a built-in NATS Server and therefore do not need this to be manually installed. If you are planning a monolith installation, you do not need to do anything.

Polylith deployments, however, currently need a standalone NATS Server installation with JetStream enabled.

To do so, follow the NATS Server installation instructions and then start your NATS deployment. JetStream must be enabled, either by passing the -js flag to nats-server, or by specifying the store_dir option in the the jetstream configuration.

Reverse proxy (polylith deployments)

Polylith deployments require a reverse proxy, such as NGINX or HAProxy. Configuring those is not covered in this documentation, although a sample configuration for NGINX is provided.

Windows

Finally, if you want to build Dendrite on Windows, you will need need gcc in the path. The best way to achieve this is by installing and building Dendrite under MinGW-w64.