Server Startup and Shutdown Sequences

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The start up and shutdown sequences consist of a number of steps that are completed in turn. If a step is unable to complete, it may cause the start up or shutdown procedure to stop.

Any issues relating to the steps in the start up and shutdown procedures are indicated in the server's log files.

The start up and shutdown sequences are described below:

Startup Sequence

The start up sequence consists of 25 steps:

• Load the database modules (drivers)

• Initialize the historian

• Initialize the data file cache. Note that this step only applies to ClearSCADA 2007 R1

• Open the configuration file

• Read the header of the configuration file and check the version number

• Read the structure of the configuration (groups, parent and child relationships etc.)

• Load the configuration of each database object

• Load the deleted object information

• Open the data file

• Load the data file and check its version number

• Load the data for each database object

• Check for errors in the load process

• Initialize the Event Journal and scan for event files on disk

• Initialize each database object

• Initialize each historic point and scan the disk for historic files

• Perform an integrity check on Group Template-Group Instance relationships

• Repair any broken Group Template-Group Instance relationships

• Check the database integrity

• Validate the configuration of each database object

• Calculate database statistics (memory usage, total amount of historic data etc.)

• Remove any historic data that is not associated with the points in the loaded configuration

• Initialize the database objects for Main-Standby transfer

• Start the database's internal housekeeping threads

• Log an event to indicate that the server has started

• Switch from using the start up log file to the main log file.
  

Typically, the start up process follows this procedure and there are no problems. However, if there are errors, the process may stop before completing or may complete with errors (the server status icon will indicate that there was an error).

Issues relating to the start up process are usually caused by:

• Missing database files
  * The data.dat file not matching the version of the ClearSCADAConfig.dat file
  * The configuration containing objects that are not supported by the ClearSCADA installation i.e. the objects relate to a driver that is not installed as part of your system.

Diagnosing Problems: You can use the log file to determine which step of the start up sequence has caused a problem - in the log file for the server, each step of the start up sequence begins with [START]. You can access the start up log file via the Server icon in the Windows taskbar.

Shutdown Sequence

The shutdown sequence consists of 12 steps:

• Stop any new incoming connections

• Send a shutdown command to all clients except those clients that use diagnostic connections

• Close all connections to non-diagnostic clients

• Stop the web server

• Stop all standby connections

• Stop internal database management threads

• Flush the Event Journal to disk

• Flush all outstanding historic data to disk

• Save the database

• Send shutdown command to diagnostic clients

• Close all diagnostic connections

• Stop the server

Each phase of the shutdown sequence is detailed in the latest log file for the server. The steps are described as step n of n, for example, step 9 or 12. If there has been a problem with the shutdown sequence, you will be able to determine which step caused the problem by looking at the last step included in the main log file (accessed via the server icon in the Windows taskbar).

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