Storage system with subdivisions

A storage system comprising:

• a solid state storage drive (SSD) comprising:
• flash memory divided into non-overlapping subdivisions of the flash memory, wherein each subdivision is mapped to at least two erase units and the erase units are on at least two different planes of the flash memory;
• and
• a host interface configured to communicate with a host using commands from a Non-Volatile Memory Express standard (NVMe commands);
• a host that communicates with the SSD using NVMe commands, wherein the host:
• transmits one or more NVMe query commands to the SSD and responsively receives:
• one or more subdivision identifiers that identify subdivisions in the SSD;
• and
• capacities for the subdivisions;
• receives information from the SSD about a specific one of the subdivisions;
• wherein the specific subdivision is identified by its subdivision identifier, and the received information includes an extent to which the erase units mapped to the specific subdivision are not yet written following an erase and can be written with data;
• and
• in response to receiving the information from the SSD, transmits one or more additional NVMe commands to the SSD, wherein the one or more additional NVMe commands identify the specific subdivision by its subdivision identifier.

A host device comprising:

• at least one processor;
• and
• a non-transitory machine readable media storing instructions that, when executed by the at least one processor, cause the host device to:
• transmit one or more NVMe query commands to a solid state storage drive (SSD), wherein the SSD comprises flash memory divided into non-overlapping subdivisions of the flash memory, and each subdivision is mapped to at least two erase units and the erase units are on at least two different planes of the flash memory;
• and the host device responsively receives:
• one or more subdivision identifiers that identify subdivisions in the SSD;
• and
• capacities for the subdivisions;
• receive information from the SSD about a specific one of the subdivisions;
• wherein the specific subdivision is identified by its subdivision identifier, and the received information includes an extent to which the erase units mapped to the specific subdivision are not yet written following an erase and can be written with data;
• and
• in response to receiving the information from the SSD, transmit one or more additional NVMe commands to the SSD, wherein the one or more additional NVMe commands identify the specific subdivision by its identifier.

A storage system comprising:

• a solid state storage drive (SSD) comprising:
• flash memory divided into non-overlapping subdivisions of the flash memory, wherein each subdivision is mapped to at least two erase units and the erase units are on at least two different planes of the flash memory;
• and
• a host interface configured to communicate with a host using commands from a Non-Volatile Memory Express standard (NVMe commands);
• a host that communicates with the SSD using NVMe commands, wherein the host:
• transmits one or more NVMe query commands to the SSD and responsively receives:
• one or more subdivision identifiers that identify subdivisions in the SSD;
• and
• capacities for the subdivisions;
• receives information from the SSD about a specific one of the subdivisions;
• wherein the specific subdivision is identified by its subdivision identifier, and the received information includes an extent to which the erase units mapped to the specific subdivision are not yet written following an erase and can be written with data;
• in response to receiving the information from the SSD, transmits one or more additional NVMe commands to the SSD for the specific subdivision, wherein the one or more additional NVMe commands identify the specific subdivision by its subdivision identifier;
• and
• the host comprises a storage manager operable to:
• track release status information for data written to the subdivisions of the flash memory;
• compare the release status information to a criterion for low utilization of segments;
• identify a subdivision based upon the comparison;
• and
• copy data from the identified subdivision to a different location.