Abstract: Systems for managing a multi-level cache in high-performance computing. A method is practiced over a multi-tier caching subsystem that comprises a first cache tier of random access memory, and a second cache tier that comprises a block-oriented device. The solid-state drive device is a block-oriented device comprising a plurality of blocks having a minimum block size. Cache entries are initially stored in the first cache, including cache entries that are smaller than the minimum block size of the block-oriented device. During cache operations such as first tier eviction, a plurality smaller entries are packed into blocks of the minimum block size before being spilled into the second tier. If an entry in the packed block is accessed again, the entire packed block is brought into the first tier. A key structure is maintained to track individual invalidated entries in a packed block without invalidating other entries in the packed block.