KBI 310209 How Daughter Engines Know Where Each Motor Is At


Argent XT — All versions


24 Aug 2010


In a Non-Stop Motor architecture, a customer may wonder how the Daughter Engine knows about the hostname/IP addresses of all Motors.

Technical Background

When a Non-Stop Motor architecture is adopted, information on all Motors in the pool are stored in a table in the central database called XX_VIRTUAL_SERVER — where XX can be replaced by the product code, e.g. AG_VIRTUAL_SERVER.

The table contains updated information on hostname, IP address, and Motor weighting, heartbeat status, etc. of all motors.

But how does a Daughter Engine get this information?

The Daughter does not store this information in the registry. The information is downloaded from any one of the Motors at each polling interval between the Daughter and the Motor, and placed into a file called CLUSTER.XML, located in the corresponding Daughter product’s data folders.

The XML file is essentially a dump of the XX_VIRTUAL_SERVER table, ensuring all Daughters know the whereabouts of each motor, and the status of each motor.