Systems and methods for identifying storage resources that are not in use

A non-transitory computer-readable medium comprising instructions, that when read by a processor, cause the processor to perform:

• receiving an empty data segment directive from a host at a storage controller, the empty data segment directive including a logical identifier associated with a physical storage location;
• returning a data string comprising predetermined data in response to a read command requesting to read data associated with the logical identifier included in the empty data segment directive;
• maintaining an index of mapping between the logical identifier and the physical storage location;
• in response to the empty data segment directive, updating the index to indicate data at the physical storage location does not need to be preserved;
• monitoring one or more physical storage locations, including the physical storage location, to determine a percentage of the one or more physical storage locations that do not need to be preserved;
• and
• initiating garbage collection on the one or more physical storage locations in response to the percentage reaching a threshold,
• wherein at least two of the following conditions individually trigger garbage collection:
• a lack of available storage capacity in one or more blocks of the one or more physical storage locations, a percentage of the physical storage locations that do not need to be preserved exceeds a first threshold, and an error detection rate for the one or more physical storage locations exceeds a second threshold.

An apparatus that manages data in a NAND flash storage system, comprising:

• a processor;
• and
• a memory, coupled to the processor, comprising instructions that when executed by the processor are configured to:
• receive an empty data segment directive from a host at a storage controller, the empty data segment directive includes a logical identifier associated with a physical storage location;
• return a data string comprising predetermined data in response to a read command that requests to read data associated with the logical identifier included in the empty data segment directive;
• maintain an index of mapping between the logical identifier and the physical storage location;
• in response to the empty data segment directive, update the index to indicate data at the physical storage location does not need to be preserved;
• monitor one or more physical storage locations, including the physical storage location, to determine a percentage of the one or more physical storage locations that do not need to be preserved;
• and
• initiate garbage collection on the one or more physical storage locations in response to the percentage reaches a threshold,
• wherein at least two of the following conditions individually trigger garbage collection:
• a lack of available storage capacity in one or more blocks of the one or more physical storage locations, a percentage of the physical storage locations that do not need to be preserved exceeds a first threshold, and an error detection rate for the one or more physical storage locations exceeds a second threshold.