Controlling the operating state of a fault-tolerant computer system

A method of controlling the operational state of a first or a second virtual machine in a fault tolerant computer system, comprising:

• monitoring, by a first availability manager running on the first virtual machine associated with a first host computer, a current health of a plurality of an immediately detectable and delayed detection operational characteristics that are associated with the first virtual machine;
• monitoring, by a second availability manager running on the second virtual machine associated with a second host computer, a current health of a plurality of an immediately detectable and delayed detection operational characteristics that are associated with the second virtual machine, wherein the fault tolerant computer system is comprised of the first and the second host computers;
• examining, by the first and second availability managers, the health of at least one of the monitored immediately detectible operational characteristics on each of the corresponding first and the second virtual machines, and if it is determined after the examination of the immediately detectible operational characteristics of the corresponding first and second virtual machines that the health of each of the first and second virtual machines is indistinguishably poor;
• then
• examining, by the first and the second availability managers, the delayed detection operational characteristics associated with the corresponding first and second virtual machines and if the examination of the delayed detection operational characteristic associated with the first and the second virtual machines indicates that at least one of the plurality of the monitored delayed detection operational characteristics associated with the first virtual machine is in poor health which causes the first virtual machine to be in poor health relative to the health of the second virtual machine, then;
• overriding, by the first availability manager, an operational state downgrade of the first virtual machine during a pre-specified deferral period of time while the health of the monitored delayed detection operational characteristic associated with the first virtual machine continues to be monitored.