1. Redundancy Hotbackup Configuration
The WIN-911 Dispatcher can be placed in Standby mode so that it tracks alarms but does not perform the notification. It can also be Activated to return to normal operation. A hot backup is a pair of WIN-911 systems where one system is ordinarily kept in Standby mode and is Activated upon a server failover.
1. Install and license two copies of the software.
2. Configure the primary system.
3. Manually place the secondary system in Standby.
4. Duplicate the primary configuration onto the secondary following the Backup Restore documentation.
5. Move a copy of Activate.exe onto the secondary SCADA.
Activate.exe - The Activate applet restores WIN-911 from Standby mode. This enables all WIN-911 notifiers.
Standby.exe - The Standby applet acts in a global manner to disable all WIN-911 monitored data points from triggering a notification. The Log Viewer will still see the alarms.
6. Edit the Activate.exe config URL host to point to the secondary WIN-911.
7. Call Activate.exe upon failover (typically through scripting).
You can use any editing software you prefer, such as Notepad. You can follow the instructions on how to apply this script. (NOTE: WIN-911 is not liable for this script)
Now that it's up and running, it's important to keep the two WIN-911 configurations the same. The easiest way to do this is to open two browser tabs and make the same edits twice, once on the primary and once on the secondary. If things get out of sync, you can run the SQL move instructions again.
Detecting failure of WIN-911 to trigger fail-over is most easily accomplished by performing an HTTP request against one or more module information svc URLs. So, you can imagine a script running on the secondary SCADA server that periodically checks for the accessibility of the primary Dispatcher and calls Activate.exe upon failure. The exact fail-over trigger is going to be application-specific. If the SCADA has a fail-over mode, then that's probably the main trigger for calling Activate on WIN-911.
Since WIN-911 is used with many different SCADA/HMI packages, the system designer is responsible for writing a script or macro to automate the execution of Standby and Activate. Below is a generic concept of how this could be achieved.
The idea here is to have one WIN-911 system in Active mode and one WIN-911 system in Standby mode. If at any time both WIN-911s are Active, double the notifications will be made for monitored alarms. If at any time both WIN-911's are in Standby, notifications will be completely lost for monitored alarms.
This script would need to be run on both WIN-911 systems:
If ActiveNode = 1
Where ActiveNode is some flag that changes when a failover occurs from your primary to secondary SCADA/HMI system.
B.1 Video Resources
To access specific parts of the video, here is a list of the topics discussed with shortcuts to the material:
- Tip 1: Use a Fallback Notifier
- Tip 2: Multiple SMS Gateways
- Tip 3: Build Contingencies into Tactics
- Tip 4: WIN-911 Advanced License
- Tip 5: Backup Server
- Hot Backup Overview
- Configuring a Hot Backup for Failover
- Summary of Redundancy Methods