Tiered caching and migration in differing granularities

A system for data processing in a distributed computing storage environment, the distributed computing storage environment incorporating at least high-speed and lower-speed caches, and tiered levels of storage, comprising:

• a processor device, operable in the computing storage environment, wherein the processor device:
• migrates groups of data segments between the tiered levels of storage such that uniformly hot ones of the groups of data segments and clumped hot ones of the groups of data segments are migrated to use a Solid State Drive (SSD) portion of the tiered levels of storage,
• determines the uniformly hot groups of data segments using a first heat map for a selected one of the group of the data segments, the heat map having a first, largest granularity,
• determines the clumped hot groups of data segments using a second heat map having a granularity smaller than the first, largest granularity of the first heat map, and
• determines sparsely hot groups of data segments by determining that neither the first heat map nor the second heat map are hotter than a first and second predetermined threshold, respectively.

A computer program product for data processing in a distributed computing storage environment by a processor device, the distributed computing storage environment incorporating at least high-speed and lower-speed caches, and tiered levels of storage, the computer program product comprising a non-transitory computer-readable storage medium having computer-readable program code portions stored therein, the computer-readable program code portions comprising:

• a first executable portion that migrates groups of data segments between the tiered levels of storage such that uniformly hot ones of the groups of data segments and clumped hot ones of the groups of data segments are migrated to use a Solid State Drive (SSD) portion of the tiered levels of storage,
• determines the uniformly hot groups of data segments using a first heat map for a selected one of the group of the data segments, the heat map having a first, largest granularity;
• determines the clumped hot groups of data segments using a second heat map having a granularity smaller than the first, largest granularity of the first heat map;
• and
• determines sparsely hot groups of data segments by determining that neither the first heat map nor the second heat map are hotter than a first and second predetermined threshold, respectively.