Let's start off by building and installing all three(Symon, Symux & Syweb). You can do this using your systems package manager or building from source. I'll be installing from OpenBSD's ports system.

Symux is the collection agent for the data generated by Symon and needs to be configured and running before we start Symon. However, Symon includes a script for scanning your system for devices to generate data on and creates a Symon configuration file. It's a bit of chicken-and-egg issue.

Now we'll execute the script for the Symon config so we have a basis of what our Symux config is going to look like. Locate c_config.sh script installed by the Symon package. In my installation it is located at /usr/local/share/symon/c_config.sh. Redirect the output from this script to /etc/symon.conf to start with. Modify this file to fine-tune what to generate data on depending on your system and monitoring requirements.

Example /etc/symon.conf:

monitor {
   cpu(0), cpu(1), mem,
   io(wd0),
   if(lo0), if(dc0), if(dc1),
   mbuf,
   pf,
   proc(httpd2), proc(mysqld), proc(squid),
   sensor(acpitz0.temp0), sensor(admtemp0.temp0),
   sensor(it0.fan0), sensor(it0.fan1)
}
 
stream to 127.0.0.1 2100

Now that we know what devices we're going to be generating data for, we can configure the Symux collection service. The main difference to note here is where the collected data is going to end up and what IP address and port the service is going to be listening on.

Example: /etc/symux.conf

mux 127.0.0.1 2100
source 127.0.0.1 {
  accept {
    cpu(0), cpu(1), mem,
    io(wd0),
    if(lo0), if(dc0), if(dc1),
    mbuf,
    pf,
    proc(httpd2), proc(mysqld), proc(squid),
    sensor(acpitz0.temp0), sensor(admtemp0.temp0),
    sensor(it0.fan0), sensor(it0.fan1)
  }
 
  datadir "/var/data/symon/rrds/localhost"
}

Great! Now the data collection and reporting services are configured. Now that we have Symux configured we can use the provided /usr/local/share/symon/c_smrrds.sh (OpenBSD) script to generate the RRD files for the devices & processes we configured in Symux. Without generating the RRDs no data will be collected and starting the services will fail.

We are now ready to start the Symux & Symon services. You must start Symux first so Symon has a place to send data to. This should be as simple as:

# /usr/local/libexec/symux
# /usr/local/libexec/symon

Don't forget to add these to your platforms start-up scripts. On OpenBSD we use /etc/rc.local

if [ -x /usr/local/libexec/symux ]; then
  echo -n ' symux';
  /usr/local/libexec/symux
fi
 
if [ -x /usr/local/libexec/symon ]; then
  echo -n ' symon';
  /usr/local/libexec/symon
fi

Perfect! Okay, now that we're collecting all this data let's look at it with Syweb. Syweb installation can be as easy as unpacking the tarball from the download directory and moving the syweb/htdocs/syweb directory to your web servers DocumentRoot. You will also need to move the .layout files located under the extracted directory syweb/symon to the layout_dir directory you specify in the Syweb setup file below.

After extracting and moving Syweb to your web servers document root(/var/apache2/htdocs/syweb) we'll want to modify Syweb's configuration to tell it where our RRDs(created by Symon & Symux) are located and where the rrdtool binary is located. This is done by modifying the setup.inc file included in the Syweb directory.

Example /var/apache2/htdocs/syweb/setup.inc:

/* running OpenBSD, apache not chrooted: */
$symon['rrdtool_path']='/usr/local/bin/rrdtool';
$symon['cache_dir']='/var/data/symon/cache';
$symon['host_tree']='/var/data/symon/rrds';
$symon['layout_dir']='/var/data/symon';

Congratulations! You should now be seeing graphs for collected Symon data by browsing to http://localhost/syweb. If you wish to modify the reports look at the .layout files in the layout_dir.

For my configuration I have a virtual host(http://syweb.domain.com) configured for this service. Whether or not you can do this depends on what type of access you have to your webservers configuration.