The database synchronization feature automatically copies the memory-resident process database (PDB) from the active SCADA node to the standby node at regular intervals. By default, to ensure that the database on the standby SCADA node is as fresh as possible, database synchronization occurs as fast as possible with very little time between synchronizations. See the Customizing the Synchronization Process with SCADASync.ini section for more information on how to modify the frequency that database synchronization occurs.
Synchronized Items
iFIX items that are synchronized as part of the database synchronization include the:
- Process Database
- SQL trigger (SQT) tasks
- SIM driver registers
- SIM signal generators and parameters
- SM2 driver registers
- Alarm counters
- Alarm logging to ODBC (relational database)
NOTE: AR and DR blocks are synchronized between nodes, however the data for these blocks resides in the driver's image table. So, during a failover, the available data is supplied by the driver.
Items that Affect Database Synchronization Performance
Items that can affect database synchronization timing include:
- Process database size
- Network speed and non-synchronization traffic
- Speed and bandwidth of hardware components
File Synchronization
In addition to synchronization of the memory-resident parts of iFIX, certain directories and files are monitored for changes. When changes to files are detected, files are copied from the active node to the standby node (never in the other direction). Therefore, any file changes made on the standby will not be synchronized to the active node. If the standby should become active, files will synchronize only if they saved after the node becomes active.
If you never want to synchronize files from the secondary node to the primary node, you can disable file synchronization on the secondary node. For more information, refer to Customizing the Synchronization Process with SCADASync.ini section.
NOTE: Be aware that if you export a database from the iFIX Database Manager on the standby SCADA or iClient (View) node, the default location will be the PDB directory of the local computer, not the SCADA node that is active.
