OSIsoft provides a buffering service that can save your data if the Interface Node loses its connection to the PI Server. When an Interface Node is running the buffering service
(bufserv), data flows from the data source, through the interface to the buffering service and from there to the Snapshot Subsystem on the PI Server
If the PI Server is not available (e.g., for an upgrade on the Server) then bufserv stores the data in a file buffer on the Interface Node. When the PI Server becomes available again, bufserv sends all the stored data from the buffer, in chronological order, back to the PI