Patent ID: 8990617
Filing Date: 2015-03-24
Classification: G06F

Abstract:
1. A fault-tolerant computer system including: a first computer that comprises a first memory and a first transfer unit, and operates a virtual machine comprising a guest Operating System (OS); and a second computer that comprises a second memory and a second transfer unit that receives data that is transferred from the first transfer unit, wherein the first computer comprises a first snapshot manager that, together with acquiring a snapshot of the virtual machine at each predetermined timing at the first computer, saves, in the first memory, difference information of a snapshot of the virtual machine at a first timing from one previous timing, and sends an instruction to the first transfer unit to transfer the difference information that is saved in the first memory to the second memory via the first transfer unit and the second transfer unit, wherein the second computer comprises a second snapshot manager that, together with generating a snapshot based on the difference information that was transferred to the second memory via the first transfer unit and the second transfer unit and saving the snapshot generated based on the difference information in the second memory, activates the guest OS in the second computer at a predetermined timing at the second computer based on the snapshot that was saved in the second memory, wherein the first computer comprises a first error handler that acquires an error information of the first computer, and sends an instruction to the first transfer unit to transfer the error information to the second computer, the second computer comprises a second error handler that, based on the error information that was sent via the first transfer unit and received via the second transfer unit, determines whether there is a failure in the first computer, and when it is determined that there is a failure, sends a computer switch notification to the second snapshot manager, and the second timing comprises a time when the second snapshot manager receives the computer switch notification, and wherein the error information includes information that indicates there is a possibility that the first computer will stop.