1. A method comprising: receiving a write request directed towards a logical unit (LUN), the write request having data, a logical block address (LBA) and a first length representing a first address range of the LUN, the write request processed at a storage system having a memory; associating a key with the data; storing the key in a first data entry of a metadata structure, the first data entry having a first offset and the first length representing the first address range of the LUN, the metadata structure having a predetermined offset and a predetermined length representing a second address range of the LUN which extends over a greater number of addresses than the first address range; merging the first data entry of the metadata structure with a second data entry of the metadata structure to form a third data entry, the second data entry having a second offset and a second length representing a third address range of the LUN, the third data entry having a third offset and a third length representing a merger of the first address range and the third address range; and storing the third data entry in a storage array of solid state drives (SSDs) attached to the storage system.