CitectSCADA allows for redundancy of the File Server. The [CtEdit]Backup parameter specifies a backup project path. If CitectSCADA cannot find a file in the Run directory (i.e. as specified by the [CtEdit]Run parameter), it will look in the backup path. If the file is found in the backup path, CitectSCADA will assume that the run path has become unavailable for some reason (for example, the file server has become inoperative). It will then look for relevant files in the backup before changing over. When CitectSCADA changes over to the backup path, it will call event number 11 and generate the hardware error: File server failed, to Standby.
File Server redundancy will only operate correctly if the redirector (or shell) on the computer can respond appropriately if the File Server becomes inoperative. The Novell Netware shell cannot do this and will cause Windows itself to become inoperative or report what it views as serious Network Errors - if the file server becomes inoperative. Microsoft LAN Manager-based networks and peer-to-peer networks correctly handle instances when the File Server becomes inoperative. Therefore, CitectSCADA File Server redundancy will operate correctly with these networks.
Note: Only CitectSCADA switches to a backup path. Any other applications that are using files on the File Server will become inoperative when the File Server becomes inoperative. This may cause the computer to wait for long periods for the File Server (or to itself become inoperative). This includes Windows itself, so install Windows on a local drive.
To enable File Server redundancy, set the [CTEDIT]Backup parameter to a backup database path. For example, if your primary path is F:\CITECT\USER\DB, set the backup path to another File Server or a local drive, such as C:\CITECT\USER\DB.
You will want to verify that the project in the Backup path is the same as the one in the Run directory - each time you compile the project in the run directory copy it into the backup directory.
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UNINTENDED EQUIPMENT OPERATION Before placing your CitectSCADA system into service, confirm that the Standby File Server has an identical copy of the current project, and that the [CTEDIT]Backup parameter is correctly set. Failure to follow these instructions can result in death, serious injury, or equipment damage. |
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