Once the defective hardware or software component has been replaced, it is brought back into service either as a new standby component or a sharer of the system load. These distinctions are somewhat arbitrary, but they nevertheless illustrate differences in system architectures. The time a system is malfunctioning, without being detected, is considered a direct outage. The ability of a system to detect all possible failures is measured in its fault coverage. Anything not covered is assigned a probability and factored in as a severe outage.
Location is implied.
Isolation and recovery are essentially the same step. All the activity is moved off of the failing node to its standby, thus isolating the defective node and recovering the system at the same time. Clustered systems essentially move from detection to recovery. Location and isolation are inherent in the architecture of the system. The complexity of the recovery process is always dependent on the specific application running on the system.