Hi, I noticed that Accumulo's LruBlockCache [1] appears to be based on HBase's. I currently have a patch being reviewed in HBASE-15560 [2] that replaces the pseudo Segmented LRU with the TinyLFU eviction policy. That should allow the cache to make better predictions based on frequency and recency, such as improved scan resistance. Full details are in the JIRA ticket. I think it should be easy to port if there is interest.
Cheers, Ben [1] https://github.com/apache/accumulo/blob/master/core/src/main/java/org/apache/accumulo/core/file/blockfile/cache/LruBlockCache.java [2] https://issues.apache.org/jira/browse/HBASE-15560
