Prioritized access for media with heterogeneous access rates

A method for assigning a physical address location to a write command in a non-volatile storage subsystem, comprising:

• performing wear leveling operations on a solid-state storage array;
• designating at least one portion of the solid-state storage array as a portion with reduced wear compared to other portions of the solid-state storage array and maintaining the designated at least one portion of the solid-state storage array as the portion with reduced wear compared to the other portions of the solid-state storage array;
• maintaining a list of available physical address locations of non-volatile storage media including the solid-state storage array, each available physical address location associated with a performance characteristic, the list being organized by the performance characteristic of the available physical address locations;
• determining a performance sensitivity associated with the write command;
• assigning the physical address location from the available physical address locations to the write command based at least in part on the determined performance sensitivity associated with the write command and the performance characteristic of the physical address location;
• wherein when the write command is received from a host, the write command is deemed to have a high performance sensitivity and is assigned an available physical address from the list corresponding to the designated at least one portion of the solid-state storage array,
• wherein when the write command is received from a management process internal to the non-volatile storage subsystem, the write command is deemed have a low performance sensitivity and is assigned an available physical address from the list corresponding to a portion of the solid-state storage array other than the designated at least one portion of the solid-state storage array,
• wherein the method is performed by a controller in the non-volatile storage subsystem.

A non-volatile storage system comprising:

• non-volatile storage media comprising a solid-state storage array, the non-volatile storage media including a higher write performance portion and a lower write performance portion;
• and
• a controller configured to:
• perform wear leveling operations on the solid-state storage array;
• designate at least one portion of the solid-state storage array as a portion with reduced wear compared to other portions of the solid-state storage array and maintain the designated at least one portion of the solid-state storage array as the portion with reduced wear compared to the other portions of the solid-state storage array, the higher write performance portion comprising the designated at least one portion of the solid-state storage array;
• receive a write command from a host;
• receive a write command from an internal component;
• maintain a list of available write locations for the non-volatile storage media;
• assign a write location to the write command from the host chosen from the list of available write locations based at least in part on a preference for assigning available write locations from the higher write performance portion of the non-volatile storage media to write commands from the host, the chosen write location assigned to the write command from the host being a memory location of the designated at least one portion of the solid-state storage array;
• and
• assign a write location to the write command from the internal component chosen from the list of available write locations based at least in part on a preference for assigning available write locations from the lower write performance portion of the non-volatile storage media to write commands from the internal component.

A non-volatile storage subsystem, comprising:

• non-volatile storage media comprising a solid-state storage array, the non-volatile storage media including a higher write performance portion and a lower write performance portion;
• and
• a controller configured to:
• perform wear leveling operations on the solid-state storage array;
• designate at least one portion of the solid-state storage array as a portion with reduced wear compared to other portions of the solid-state storage array and maintain the designated at least one portion of the solid-state storage array as the portion with reduced wear compared to the other portions of the solid-state storage array, the higher write performance portion comprising the designated at least one portion of the solid-state storage array;
• maintain a list of available write locations for the non-volatile storage media;
• receive a write command comprising a logical address and write data;
• determine a performance sensitivity associated with the write command in part based on a run-time characteristic of the non-volatile storage subsystem and whether the write command is received from a host system or a maintenance process internal to the non-volatile storage subsystem;
• and
• select a write location either in the higher write performance portion or the lower write performance portion of the storage media chosen from the list of available write locations based at least in part on the determined performance sensitivity associated with the write command.