System and method for maintaining a data redundancy scheme in a solid state memory in the event of a power loss

A method of maintaining data redundancy in a solid-state storage subsystem in the event of a power interruption, the method comprising:

• implementing a data redundancy configuration with a plurality of data stripes in a non-volatile memory array of the solid-state storage subsystem;
• temporarily storing data to be written to the non-volatile memory array in a write cache of the solid-state storage subsystem;
• moving data stored in the write cache to the non-volatile memory array, the data being moved in a size increment matching a pre-defined size of the data stripes in the data redundancy configuration;
• and
• when a shutdown of the storage subsystem begins while a quantity of data in the write cache is less than the pre-defined data stripe size, writing the cached data to the non-volatile memory array to form a partial data stripe of the data redundancy configuration.

A solid-state storage subsystem comprising:

• a non-volatile memory array;
• a backup power source for supplying backup power to the storage subsystem in the event of a power interruption;
• a controller configured to:
• receive data to be written to the non-volatile memory array;
• write the received data to the non-volatile memory array as a plurality of data stripes as part of a data redundancy configuration, each data stripe being of a pre-defined stripe size;
• create parity data for each stripe;
• and
• in response to detecting a power interruption to the storage subsystem,
• use the backup power to write the received data as a partial data stripe that is smaller than the pre-defined stripe size when a quantity of the received data not yet written is insufficient to create a data stripe of the pre-defined size, and
• create parity data for the partial data stripe, thereby reducing an amount of power in the backup power source needed to enable the controller to provide parity protection for the received data in the event of a power interruption.