Hybrid-HDD that limits dirty data in NAND

摘要

A hybrid hard disk drive (HDD) that includes a magnetic storage medium and a nonvolatile solid-state device limits the amount of data that are stored in the solid-state storage device but are not also stored in the magnetic storage device. By limiting such “flash-only” data to as much as can be flushed to the magnetic storage medium within a specified time, the hybrid HDD can flush all flash-only data to the magnetic storage medium immediately prior to a power-off of the drive. Thus, the hybrid HDD can employ a write cache, which relies on storing flash-only data in the hybrid HDD, without the disadvantage of storing flash-only data after shut-down.

主权项

1. A data storage device comprising:
a nonvolatile solid-state storage device; a magnetic storage device that includes a magnetic disk; and a controller configured to track flash-only data, which are data that are stored in the solid-state storage device and are not also stored in the magnetic storage device; receive a write command; determine an estimated time to write for the flash-only data and write data associated with the received write command to be stored in the magnetic storage device; cause the write data to be stored in the nonvolatile solid-state device if the estimated time is less than a target time; and cause the write data to be stored in the magnetic storage device if the estimated time is greater than the target time.