Polling is the active watching, or monitoring, of your network with WhatsUp Gold. This is done in a variety of ways, depending on the service monitors you have configured on your devices. The default polling method is accomplished through Internet Control Message Protocol (ICMP). The default polling interval for WhatsUp Gold is 60 seconds.
A small amount of data is sent from the WhatsUp Gold computer across the network to the device it is watching. If the device is up, it echoes the data back to the WhatsUp Gold computer. WhatsUp Gold considers a device is down when it does not send the data back.
It's important to note that polling interval settings affect how WhatsUp Gold determines a specific device state. For example, if a user has specified that she only wants to poll a device every 5 minutes, WhatsUp Gold will only recognize device state changes at the 5 minute polling intervals. If a device has been down 2 minutes, it will be recognized as down when the 5 minute polling interval occurs. Corresponding Up actions will be triggered after the 5 minute poll occurs rather than when the device went down at the two minute point.
The device polling interval affects the way WhatsUp Gold determines the specific device state. When a device transitions from Up to Down, it checks to determine the last time the device was Up. For example, with the default polling interval of 60 seconds, when a device goes down it looks back and determines that the last time it was up was 63 seconds ago so it goes from "Up at least 5" to "Down." In the next polling interval when the device still returns down, WhatsUp Gold looks backward and determines that the last Up time was 125 seconds ago so it now is "Down at least 2 minutes."
If a 5 minute polling interval is set, the first time that a device returns down, WhatsUp Gold looks back and determines that the last time the device was up was 304 seconds ago so it transitions directly from "Up at least 5 minutes" to "Down at least 5 minutes" (skipping the Down and Down 2 states). Similarly, when the device comes back up, WhatsUp Gold looks back to determine the last time the device was Down and it registers that it was 301 seconds ago so it transitions directly from "Down at least 5" to "Up at least 5 minutes."
In short, if you plan to use polling intervals longer than the default of 60 seconds, we recommend that you associate actions with device states that will not be skipped because of the extended polling interval.
An average poll lag time of a few seconds or more indicates your system may not be performing optimally. If WhatsUp Gold device polling seems to be experiencing performance lag, use the Poller Health dashboard report to assess and confirm poller performance. The WhatsUp Gold CPU and memory utilization reports can also be used to indicate performance issues. There are a number of ways to improve poller performance by reducing the workload of the WhatsUp Gold machine.
The recommended option is adding one or more additional pollers to your WhatsUp Gold system depending on the size of your network. When additional pollers are installed, load balancing should be disabled on the local poller. This transfers the majority of the polling workload to the additional pollers, reserving the local poller for polling activity on the WhatsUp Gold server. However, if your network is distributed across a large geographic area, you may benefit from assigning a poller to a specific subnet or device. In this case, load balancing should also be disabled on the specific poller to limit its activity to the assigned device(s). Please refer to Using Scalability Pollers with WhatsUp Gold for more details.
Other options include removing the local poller from the load balancing queue which reduces the workload of the WhatsUp Gold server and allows it to perform other tasks for which it is responsible or relocating your SQL instance to a machine separate from your WhatsUp Gold server.
If you are still experiencing polling performance issues, consider adding additional memory and increasing disk speed on the machine hosting your SQL instance and/or adding or assigning a machine on your WhatsUp Gold system dedicated solely to polling operations.