Hypervisor Processor Replacement Logic for Logical Partitions

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Solution Overview

Problem

In computer systems with multiple logical partitions, the lack of unused processors for replacement during failures leads to system termination or performance degradation, as chance selection of failing processors can result in suboptimal partition suffering.

Innovation Solution

A method where a hypervisor assigns priorities to partitions, detects failing processors, retrieves their state, and replaces them with a processor from a lower-priority partition, ensuring seamless operation by assigning the retrieved state to the replacement processor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If unused processors are kept available for replacement, then system reliability is improved, but resource utilization deteriorates

Engineering Contradiction:
Improvesystem availabilityVSAvoidprocessor resource waste
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The system dynamically reassigns processors between partitions based on failure events and priority levels. When a processor fails, the hypervisor dynamically selects a replacement from lower-priority partitions and reassigns it, rather than relying on static unused processors. This dynamic reallocation maintains reliability while eliminating the need for dedicated spare processors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational state of processors by modifying their partition assignments. Processors are reassigned from lower-priority partitions to higher-priority partitions when failures occur, changing the parameter of processor utilization from idle/wasted to actively serving critical partitions. This parameter change resolves the contradiction by making previously wasted resources productive.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If processors are reassigned from lower-priority partitions, then system reliability is improved, but performance of lower-priority partitions deteriorates

Engineering Contradiction:
Improvepartition availabilityVSAvoidlower-priority partition performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system inverts the traditional approach by allowing lower-priority partitions to be temporarily degraded so that higher-priority partitions can maintain availability. Instead of protecting all partitions equally, the system deliberately allows lower-priority partitions to suffer performance degradation or temporary unavailability, which in turn protects the overall system by ensuring critical partitions remain operational.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The system applies different quality levels of service to different partitions based on their priority assignments. Higher-priority partitions receive guaranteed processor availability and faster replacement, while lower-priority partitions accept reduced service quality. This local differentiation resolves the contradiction by concentrating resources where they are most needed.

Inventive Principle:
Principle #3Local quality

3Speed

If complete processor state information is maintained, then recovery speed is improved, but memory usage increases

Engineering Contradiction:
Improveprocessor replacement speedVSAvoidmemory consumption
Core Design Contradiction:
SpeedVSQuantity of substance

Solution Approach 1:

The hypervisor performs preliminary actions by maintaining processor state information in memory before failures occur. This preliminary preparation allows instantaneous restoration when processors fail, as the state is already captured and ready for reassignment. The memory consumption is a necessary investment that enables rapid recovery without requiring time-consuming state capture during failure events.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1943590B1Assigning a processor to a logical partition and replacing it by a different processor in case of a failure
Publication Date: 2013.03.06 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • EP1943590B1 patent drawingFigure 1
  • EP1943590B1 patent drawingFigure 2
  • EP1943590B1 patent drawingFigure 3

AI summary

Assigning a processor to a logical partition in a computer supporting multiple logical partitions that include assigning priorities to partitions, detecting a checkstop of a failing processor of a partition, retrieving the failing processor's state, replacing by a hypervisor the failing processor with a replacement processor from a partition having a priority lower than the priority of the partition of the failing processor, and assigning the retrieved state of the failing processor as the state of the replacement processor.