Shutdown events

PI points have a configurable attribute, Shutdown, to determine whether shutdown events are written. The time stamp of the shutdown event normally represents the actual shutdown time of Data Archive as recorded by PI Snapshot Subsystem. If Data Archive shuts down ungracefully, this time stamp is accurate to within 15 minutes by default.

Valid values for the Shutdown attribute are 1 (On) and 0 (Off). If a point's Shutdown attribute is 1, then PI Shutdown Subsystem writes a shutdown event whenever Data Archive shuts down. Unless you configure points to receive shutdown events, only test points such as sinusoid and sinusoidu receive shutdown events.

For points collected by remote interfaces that are configured for buffering or high availability (HA), we recommend the default setting of 0 (Off). This is because if you run remote interfaces with buffering or PI Server collectives, shutdown events are not an accurate indicator of data loss when Data Archive shuts down. With properly configured buffering, data simply queues up for Data Archive while it is shut down, provided the remote interfaces continue running. Also, if Data Archive is part of a collective, shutting down one member has no effect on the other members' ability to continue receiving and serving data.

Many sites configure points that store laboratory test values so that the lab test points do not receive shutdown events. Lab values are assumed to be constant between tests. Inserting shutdown events for these points can be misleading.

Note: We recommend that you do not run interfaces on the same machine as Data Archive. However, if you do use such a configuration, configure these local interfaces for shutdown events. Unlike most Data Archive subsystems, PI Shutdown Subsystem exits after completion.