ORCA Recovery Features

Overview

ORCA includes features that allow containers with actors to be shut down and brought back up without affecting actors in other containers. ORCA actors save their state in MySQL database and upon restart of the container can recreate the pre-shutdown state. This feature can be selectively turned on and off on a per-container basis.

Operation

Upon startup of the webapp/container ORCA creates a file $ORCA_HOME/state_recovery.lock. If when the container is re-started the file is present, ORCA will attempt to read its state from the database and restore actors to pre-shutdown state. If the file is not there, ORCA starts with a clean state. If you wish to start the container clean, remove the file just before starting the container.

Note: If you are restarting an Authority actor, its delegations to Brokers remain unaffected. If you wish to restart an Authority actor "clean", close all of its delegations to brokers (in the broker actors) and then restart the authority actor after removing the $ORCA_HOME/state_recovery.lock file. You will have to create new delegations and perform new claims from the brokers after that.