The invention addresses these and other problems associated with the prior art by providing an apparatus and program product that utilize event-driven reoptimization to reallocate one or more logical partitions within a pool of logically-partitioned data processing systems in response to detection of a system event that is likely to increase or decrease the collective resource demands of logical partitions resident in a logically-partitioned computing environment. In some instances, for example, the reoptimization may be used to consolidate logical partitions on fewer processor nodes to improve the potential for powering down hardware resources and thereby reduce power consumption.