System and Method for Eviction and Replacement in Large Content-Addressable Flash Caches

In a processing system in which at least one entity issues data read and write requests to at least one storage system that stores data as data units, pluralities of data units are grouped. Each group is written as a respective cache line in a cache, which is deduplicated. Before evicting a selected one of the cache lines, a caching component determines whether at least one of the data units in the selected cache line is still active; if so, then the still active data unit(s) in the selected cache line is read and written to a different cache line.