Systems, methods, and computer readable media for lazy compression of data incoming to a data storage entity

A system for lazy compression of data incoming to a data storage entity, the system comprising:

• a plurality of data storage devices having non-volatile data storage space for storing data, the collective data storage space being divided into a plurality of slices for allocation to at least one logical unit, wherein at least one logical unit is a compressed logical unit occupying a predefined logical block address space and divided into a plurality of chunks, wherein for each chunk, data may be stored in compressed form or stored in uncompressed form and later compressed and wherein each chunk comprises an independent compression domain;
• and
• a controller for receiving input/output requests from hosts and for controlling the data storage devices, the controller further including:
• a first module for receiving a command to write data to a logical block address within the compressed logical unit, and, in response to receiving the command to write data to the logical block address within the compressed logical unit, identifying a target chunk within the compressed logical unit corresponding to the logical block address, determining whether data in the target chunk to be modified by the command exists on the logical unit as compressed or uncompressed data, and if the data to be modified exists on the logical unit as compressed data, determining whether the data to be written to the target chunk by the command will completely overwrite all of the data in the target chunk, and if the data to be written to the target chunk by the command will completely overwrite all of the data in the target chunk, writing the data to the target chunk without uncompressing the data in the target chunk and if the data to be written to the target chunk by the command will not completely overwrite the data in the target chunk, uncompressing the data, modifying the uncompressed data, and writing the data to the target chunk of the compressed logical unit in uncompressed form;
• and
• a second module for monitoring for a trigger condition, and, upon detection of a trigger condition, compressing uncompressed data within the target chunk of the compressed logical unit.

A non-transitory computer readable medium having stored thereon executable instructions that when executed by the processor of a computer control the computer to perform steps comprising:

• in a data storage entity having a plurality of data storage devices whose collective data storage capacity defines a non-volatile data storage area, defining at least a portion of the data storage area within the data storage entity as a compressed logical unit occupying a predefined logical block address space and divided into a plurality of chunks, wherein for each chunk, data may be stored in compressed form or stored in uncompressed form and later compressed and wherein each chunk comprises an independent compression domain;
• at a controller for receiving input/output requests from hosts and for controlling the data storage devices:
• receiving a command to write data to a logical block address within the compressed logical unit, and, in response to receiving the command to write data to logical block address within the compressed logical unit, identifying a target chunk within the compressed logical unit corresponding to the logical block address, determining whether data in the target chunk to be modified by the command exists on the logical unit as compressed or uncompressed data, and if the data to be modified exists on the logical unit as compressed data, determining whether the data to be written to the target chunk by the command will completely overwrite all of the data in the target chunk, and if the data to be written to the target chunk by the command will completely overwrite all of the data in the target chunk, writing the data to the target chunk without uncompressing the data in the target chunk and if the data to be written to the target chunk by the command will not completely overwrite the data in the target chunk, uncompressing the data in the target chunk, modifying the uncompressed data, and writing the modified data to the target chunk of the compressed logical unit in uncompressed form;
• and
• monitoring for a trigger condition, and, upon detection of a trigger condition, compressing uncompressed data within the target chunk of the compressed logical unit.