1. A method comprising: in a storage system, optimizing a cache storage layer, including classifying data storage cache into a primary cache section and a secondary cache section; differentiating blocks of data based on an inherent sharing characteristic of the data block; and utilizing the optimized cache storage layer responsive to the inherent characteristic of the data block, including placing one or more data blocks into one of the classified sections of the cache storage layer, the placement reflecting sharing of the data blocks among virtual disk images access by virtual machines.