PrismResiliencyService

Prism Resiliency ServiceEven the most reliable Internet connections may occasionally suffer a loss of connectivity. For merchants, even a brief interruption in the connection with the server can result in significant losses. RP Prism Centrals includes an offline mode to gracefully handle situations in which the connection to the Centrals server is lost.
When resiliency is enabled and the connection to the Centrals server is lost, Prism will continue to allow you to make transactions. In the case of Central Credit, you can define an Offline Take Limit that places a ceiling on the amount for any single offline transaction. When the connection is restored, transactions completed when the centrals server was offline are sent to the Centrals Server.
Offline mode' is defined as ‘Centrals Service not available'. This could be caused by a variety of problems, including:

• The Centrals hostname/IP address was entered incorrectly and cannot be found
• The Centrals server is down
• The Centrals Server is up, but the PrismPOSV1 service on the Centrals server is not running.

The frequency with which resiliency tries to re-connect to the Centrals server is the ‘Interval' value (in minutes) defined in Admin Console > Installation Defaults. Enter the number of minutes Prism should wait before checking again to see if the connection to the Centrals server has been restored. For example, entering a value of 5 means that a check will be done every five minutes until the connection is restored.
PrismResiliencyService.exe
The Prism Server Installer adds the PrismResiliencyServer.exe to the file system and installs the PrismResiliencyService in the C:\Program Files (x86)\RetailPro\Resiliency\ folder. The PrismResiliencyService.exe facilitates the ability to create Central Credit and Central Gift Card transactions while offline. The Resiliency service will run automatically according to the Interval defined in Installation Defaults. You can run the service outside of the interval by clicking the "Run Resiliency" button. 
Reference: Chapter 31. Centrals