Dynamic Processor Deallocation

AIX can detect and automatically stop using a faulty processor.

Starting with machine type 7044 model 270, the hardware of all systems with two or more processors is able to detect correctable errors, which are gathered by the firmware. These errors are not fatal and, as long as they remain rare occurrences, can be safely ignored. However, when a pattern of failures seems to be developing on a specific processor, this pattern might indicate that this component is likely to exhibit a fatal failure in the near future. This prediction is made by the firmware based on the failure rates and threshold analysis.

On these systems, AIX implements continuous hardware surveillance and regularly polls the firmware for hardware errors. When the number of processor errors hits a threshold and the firmware recognizes that there is a distinct probability that this system component will fail, the firmware returns an error report. In all cases, the error is logged in the system error log. In addition, on multiprocessor systems, depending on the type of failure, AIX attempts to stop using the untrustworthy processor and deallocate it. This feature is called Dynamic Processor Deallocation.

At this point, the processor is also flagged by the firmware for persistent deallocation for subsequent reboots, until maintenance personnel replaces the processor.