Zero detection within sub-track compression domains

An apparatus comprising:

• a block-based storage array that presents a logical volume of storage to a host application, the logical volume of storage having contiguous logical block addresses, the storage array comprising:
• a plurality of tangible data storage drives;
• metadata that maps the contiguous logical block addresses to a non-contiguous physical address set on the tangible data storage drives;
• and
• a computing node comprising a processor and a cache, the computing node using only a single fixed-size allocation unit of storage capacity in commands to read and write uncompressed data from and to the data storage drives, wherein the single fixed-size allocation unit is larger than a smallest size unit of storage capacity that the tangible data storage drives can process, wherein the computing node is responsive to commands from the host application to access logical blocks of the production volume to use the metadata to access corresponding physical addresses of the tangible data storage drives, and wherein the computing node:
• causes a first fixed-size allocation unit of production volume data to be stored on the tangible data storage drives;
• reorganizes the first fixed-size allocation unit into a plurality of same-size sub-allocation units that are smaller in size than the first fixed-size allocation unit and larger than the smallest size unit of storage capacity that the tangible data storage drives can process, each sub-allocation unit being a separate compression domain that defines which data is interdependently compressed and de-compressed;
• determines that a first sub-allocation unit of the plurality of sub-allocation units matches a known pattern;
• represents the first sub-allocation unit with a first pattern identifier;
• determines that a second sub-allocation unit of the plurality of sub-allocation units does not match the known pattern;
• causes the second sub-allocation unit to be stored on the tangible data storage drives;
• and
• responsive to a read from the host application, generates the first sub-allocation unit in the cache using the pattern identifier without accessing the data storage drives and without decompressing the first sub-allocation unit.