Efficient cache eviction and insertions for sustained steady state performance

A distributed metadata cache for a distributed object store, the distributed metadata cache comprising:

• a plurality of cache entries, each cache entry including information relating to whether at least one input/output (IO) thread is actively referencing the cache entry and information relating to whether the cache entry is no longer referenced by at least one IO thread;
• and
• an active-cache-entry set, each cache entry in the active-cache-entry set including information that indicates that at least one IO thread is actively referencing the cache entry;
• and
• an unreferenced-cache-entry set, each cache entry in the unreferenced-cache-entry set being eligible for eviction from the distributed metadata cache by including information that indicates that the cache entry is no longer actively referenced by an IO thread;
• and
• a pool of free resources that is available to become a cache entry in response to an IO thread.