US 12,468,466 B2
Method to keep on-disk physical deduplication index layer up to date
Uri Shabi, Tel Mond (IL); Alexander Shknevsky, Fair Lawn, NJ (US); and Amit Zaitman, Shavey Shomron (IL)
Assigned to Dell Products L.P., Round Rock, TX (US)
Filed by Dell Products L.P., Round Rock, TX (US)
Filed on Apr. 18, 2024, as Appl. No. 18/638,979.
Prior Publication US 2025/0328271 A1, Oct. 23, 2025
Int. Cl. G06F 3/00 (2006.01); G06F 3/06 (2006.01)
CPC G06F 3/0641 (2013.01) [G06F 3/0604 (2013.01); G06F 3/067 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method comprising:
providing a plurality of deduplication (“dedupe”) indexes across a memory level and a disk level of a storage system, the plurality of dedupe indexes including an in-memory dedupe index at the memory level, and an on-disk dedupe index at the disk level, the plurality of dedupe indexes for use by the storage system in performing data deduplication operations;
applying a plurality of eviction rules regarding evicting digest entries of the on-disk dedupe index, the plurality of eviction rules avoiding random evictions of digest entries from the on-disk dedupe index;
in response to applying the plurality of eviction rules, identifying a number of digest entries of the on-disk dedupe index as eviction candidates; and
evicting the identified eviction candidates from the on-disk dedupe index,
wherein each of the plurality of dedupe indexes includes a plurality of digest entries, each digest entry including a digest of a stored dataset and a pointer to information pertaining to a location of the stored dataset, and
wherein the applying a plurality of eviction rules includes:
applying a first eviction rule including avoiding removing or evicting digest entries for stored datasets pointed to by virtual pointers having a reference count with a first value greater than a predetermined maximum reference count;
applying a second eviction rule including preferring removing or evicting digest entries for stored datasets pointed to by virtual pointers having the predetermined maximum reference count;
applying a third eviction rule including preferring removing or evicting digest entries for stored datasets deemed non-deduplicable; and
applying a fourth eviction rule including avoiding removing or evicting “clean” digest entries previously destaged from the in-memory dedupe index.