Patent ID: 8627004
Filing Date: 2014-01-07
Classification: G06F

Abstract:
1. A method for data migration between each of a plurality of storage pools organized into extent tiers in a computing storage environment by a processor device, comprising: categorizing each of the plurality of storage pools by a metric shared between data segments assigned to any one of the plurality of storage pools, wherein the plurality of storage pools includes a child pool and a parent pool, the data segments are prioritized in the any one of the plurality of storage pools based on the metric, and the metric includes at least one of write or read counter data, a last time a data segment was promoted, and a flag initializing a corresponding data segment to false; iterating each child pool and each of the plurality of storage pools in all extent tiers with a reversed n level-order traversal and performing, for each of the plurality of storage pools: discovering, on a predetermined interval and based on the metric, whether a priority of a data segment with a lowest priority on the child pool of the plurality of storage pools is less than a priority of a data segment with a highest priority on the parent pool of the priority of storage pools, determining whether a least frequently accessed data segment exists unmodified within a child promotion queue, if the priority of the data segment with the lowest priority on the child pool is less than the priority of the data segment with the highest priority on the parent pool; dequeuing the data segment from the child promotion queue, if the least frequently accessed data segment exists unmodified within the child promotion queue; determining whether room is available in the child pool to include the data segment; and demoting the data segment with the highest priority on the parent pool to the child pool if room is available; wherein pursuant to the demoting the data segment with the highest priority on the parent pool to the child pool, a copy of the data segment with the highest priority on the parent pool is retained to allow for migration back in constant time.