Bandwidth Usage in a PRTG Cluster

• A PRTG cluster only transfers changes. If all sensors are up and running and no editing is done to sensors/devices/etc. no data is transferred between the nodes of your PRTG cluster.

• There is a "keep alive" message from each node every 10s, but that does not scale with the sensor count.

• At start-up or if the nodes are out of sync, there can be a transfer spike when the whole configuration (in a compressed form) is sent to the other nodes. You can have a look at the size of your configuration file (as said, it's sent compressed however), but as this varies from user to user, it's impossible to name an exact number here.

• If sensors go up or down, the status is broadcast to all other nodes. The traffic caused by this depends on the number of nodes.

• If the core installation on one of the nodes is updated, the setup file (about 36MB) is transferred to the other nodes to automatically update them.

• When reviewing monitoring data including different nodes, the required data (states, graphs, tables, etc.) is transferred from the other nodes to the one you're logged in. Especially graphs with "all nodes" selected can cause traffic peaks. This affects reports with "all nodes", too.

• In a cluster, every PRTG node independently monitors the devices added to the "Cluster Probe". Each of those devices sends monitoring data to every single cluster node. This causes extra traffic, depending on the number of nodes used. Note: Especially when using many WMI sensors, this can lead to extended traffic on the hosts.