# MaxScale 21.06 Read-Write Splitting with MariaDB MaxScale

The goal of this tutorial is to configure a system that appears to the client as a single\
database. MariaDB MaxScale will split the statements such that write statements are sent\
to the master server and read statements are balanced across the slave servers.

### Setting up MariaDB MaxScale

This tutorial is a part of [MariaDB MaxScale Tutorial](https://mariadb.com/docs/maxscale/maxscale-archive/archive/mariadb-maxscale-21-06/mariadb-maxscale-21-06-tutorials/mariadb-maxscale-2106-maxscale-2106-setting-up-mariadb-maxscale).\
Please read it and follow the instructions. Return here once basic setup is complete.

### Configuring the service

After configuring the servers and the monitor, we create a read-write-splitter service\
configuration. Create the following section in your configuration file. The section name\
is also the name of the service and should be meaningful. For this tutorial, we use the\
name *Splitter-Service*.

```
[Splitter-Service]
type=service
router=readwritesplit
servers=dbserv1, dbserv2, dbserv3
user=maxscale
password=maxscale_pw
```

*router* defines the routing module used. Here we use *readwritesplit* for\
query-level read-write-splitting.

A service needs a list of servers where queries will be routed to. The server names must\
match the names of server sections in the configuration file and not the hostnames or\
addresses of the servers.

The *user* and *password* parameters define the credentials the service uses to populate\
user authentication data. These users were created at the start of the [MaxScale Tutorial](https://mariadb.com/docs/maxscale/maxscale-archive/archive/mariadb-maxscale-21-06/mariadb-maxscale-21-06-tutorials/mariadb-maxscale-2106-maxscale-2106-setting-up-mariadb-maxscale).

For increased security, see [password encryption](https://mariadb.com/docs/maxscale/maxscale-archive/archive/mariadb-maxscale-21-06/mariadb-maxscale-21-06-tutorials/mariadb-maxscale-2106-maxscale-2106-encrypting-passwords).

### Configuring the Listener

To allow network connections to a service, a network ports must be associated with it.\
This is done by creating a separate listener section in the configuration file. A service\
may have multiple listeners but for this tutorial one is enough.

```
[Splitter-Listener]
type=listener
service=Splitter-Service
port=3306
```

The *service* parameter tells which service the listener connects to. For the\_Splitter-Listener\_ we set it to *Splitter-Service*.

A listener must define the network port to listen on.

The optional *address*-parameter defines the local address the listener should bind to.\
This may be required when the host machine has multiple network interfaces. The\
default behavior is to listen on all network interfaces (the IPv6 address `::`).

### Starting MariaDB MaxScale

For the last steps, please return to [MaxScale Tutorial](https://mariadb.com/docs/maxscale/maxscale-archive/archive/mariadb-maxscale-21-06/mariadb-maxscale-21-06-tutorials/mariadb-maxscale-2106-maxscale-2106-setting-up-mariadb-maxscale).

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