Abstract: In part, in one aspect, the disclosure relates to a preparing for a standby compute node for a migration event in a fault tolerant system. The method may include receiving a migration instruction at the standby compute node of the fault tolerant system, the standby compute node includes a processor, a memory and an operating system; initiating a system service on the standby compute node, wherein the system service is configured to start a shutdown or a reboot process of the standby compute node; and quiescing one or more devices in communication with the standby node.

Abstract: In part, in one aspect, the disclosure relates to a method of monitoring an active compute node in a fault tolerant system. The method may include monitoring a boot process of a first compute node by interrogating one or more watchdog timers running on the first compute node during the boot process; determining a boot process outcome for the first compute node, wherein the boot process outcome is a failure if the one or more of the watchdog timers exceeds a threshold time indicative of normal boot operation; performing a first action if the outcome is a failure; and performing a second action if the outcome is not a failure.

Abstract: A method for tracking modified pages is provided. The method is utilized in a fault-tolerant system, the fault-tolerant system comprising a first computer system and a second computer system. The method involves copying a memory from the first computer system to the second computer system at a first point in time. Between the first point in time and a second point in time, a scheduler tracks processes that execute on the first computer system in a harvest list. After the second point in time, the processes that made changes to the memory between the first and second points in time are retrieved. The changes to the memory are then copied to the second computer system and the changes are applied to the memory of the second computer system.