US 12,405,729 B2
Log-structured data storage system using flexible data placement for reduced write amplification and device wear
Lior Kamran, Richon LeZion (IL); Uri Shabi, Tel Mond (IL); Steven A. Morley, Mendon, MA (US); and Amitai Alkalay, Kadima (IL)
Assigned to Dell Products L.P., Round Rock, TX (US)
Filed by Dell Products L.P., Round Rock, TX (US)
Filed on Aug. 25, 2023, as Appl. No. 18/237,982.
Prior Publication US 2025/0068330 A1, Feb. 27, 2025
Int. Cl. G06F 3/06 (2006.01); G06F 12/02 (2006.01)
CPC G06F 3/0616 (2013.01) [G06F 3/0608 (2013.01); G06F 3/0644 (2013.01); G06F 3/0652 (2013.01); G06F 3/0688 (2013.01); G06F 12/0253 (2013.01); G06F 2212/262 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A method of performing system-level garbage collection in a data storage system employing log-structured writing of data, the data storage system including a set of solid-state drive (SSD) storage devices providing underlying physical storage for the data, comprising:
identifying respective reclaim unit sizes of the storage devices, each storage device having reclaim units of the respective size, each reclaim unit being a unit of programming and erasure used by device-level garbage collection to regularly generate erased reclaim units for allocation for physical data storage, the reclaim unit sizes being respective power-of-2 multiples of a base reclaim unit size R;
arranging the data across the physical storage devices in first and second data units, each first data unit being of a first size U equal to the product of R and a stripe width W of storage devices across which the first data unit extends, each second data unit including a respective set of first data units which occupy a maximum-size reclaim unit of a respective storage device among the storage devices across which the set of first data units extend; and
operating the system-level garbage collection with second-data-unit granularity to regularly generate empty second data units for allocation in the log-structured writing of data.