Active data placement on cache eviction

Abstract

A data storage system with interconnected compute nodes includes a shared memory with volatile and non-volatile portions. Data tracks evicted from the volatile portion are moved to the non-volatile portion based on a cache-miss interarrival rate threshold that is calculated based on capacity and fall-through time of the non-volatile portion of the shared memory. Data extents on non-volatile drives are characterized based on dominant modes of extent-level cache-miss interarrival histograms generated using countdown timers of most recent backend accesses of sub-extents. The dominant mode of the extent in which a backend track evicted from the volatile portion of the shared memory resides is compared with the threshold in order to determine whether to move the backend track to the non-volatile portion of the shared memory.

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