A technique for managing data storage in a data storage system is disclosed. Data blocks are written to a data storage system cache, pluralities of the data blocks being organized into cache macro blocks, the IO cache macro blocks having a fixed size. Access requests for the data blocks are processed, wherein processing includes generating block access statics. Using access statics, data blocks stored in the cache macroblocks having block a access times that overlap are identified. Data blocks identified as having overlapping access times are rearranged into one or more overlap cache macroblocks. Data storage system cache memory is arranged into multiple input/output (IO) cache macroblocks, where a first set of IO cache macroblocks are configured as compressed IO cache macro blocks, each compressed IO cache macro block storing a plurality of variable sized compressed IO data blocks, and a second set of IO cache macroblocks are configured as non-compressed IO cache macroblocks, each non-compressed IO cache macroblock storing a plurality of fixed sized non-compressed IO data blocks. A write request is receive at the data storage system. If the IO data associated with the write request is determined to be compressible, the IO data is compressed in-line and written to an IO data block in a compressed IO cache macroblock, otherwise non-compressed IO data is written to an IO data block in a non-compressed IO cache macroblock.