Abstract: Techniques using process-pair protection of complex applications are disclosed which provide fast and stateful application failover.

Abstract: A method and apparatus for providing process-pair protection to complex applications is provided. The apparatus of the present invention includes a process-pair manager or PPM. The PPM is replicated so that a respective PPM is deployed on each of two computer systems. Each computer system also hosts a watchdog process that monitors and restarts the PPM in case of PPM failures. Each PPM communicates with a respective instance of an application. The application instances may include one or more processes along with associated resources. During normal operation the primary application provides service and periodically checkpoints its state to the backup application. The backup application functions in a standby mode. The two PPMs communicate with each other and exchange messages as state changes occur. The apparatus also includes in each computer system a node watcher that is the PPM of failures of the remote computer system.

Abstract: A method and apparatus for providing paired or shadowed shared memory within UNIX and UNIX-like environments is provided. For the present invention shared memory segments, established using System V-like shared memory commands, are registered or paired. Once paired checkpointing operations may be performed by pushing or pulling data between paired segments. These checkpointing operations may be synchronous or asynchronous. The present invention also allows client processes to determine the status of shared memory segments and the status of checkpointing requests.