US 11,868,335 B2
Space-efficient change journal for a storage system
Anand Apte, Pune (IN); and Alok Kumar, Bihar (IN)
Assigned to Druva Inc., Sunnyvale, CA (US)
Filed by DRUVA INC., Sunnyvale, CA (US)
Filed on Jul. 30, 2019, as Appl. No. 16/526,284.
Claims priority of application No. 201941020272 (IN), filed on May 22, 2019.
Prior Publication US 2020/0372005 A1, Nov. 26, 2020
Int. Cl. G06F 16/23 (2019.01); G06F 16/22 (2019.01)
CPC G06F 16/2358 (2019.01) [G06F 16/2246 (2019.01)] 11 Claims
OG exemplary drawing
 
1. A change journal for a storage system, the storage system comprising:
a memory having computer-readable instructions stored therein;
a processor configured to execute the computer-readable instructions to:
store, in storage site, metadata of a plurality of files and the plurality of files received from an application in accordance with a backup schedule of the application;
organize the stored metadata of the plurality of files using a log-structured merge-tree (LSM tree);
access the log-structured merge-tree (LSM tree) that comprises a first plurality of first indices placed in a plurality of indexing layers, wherein a second plurality of the first indices in one indexing layer of the indexing layers is merged, in response to updates to the metadata, into another index at a higher indexing layer of the indexing layers than the one indexing layer, and wherein a third plurality of the first indices is (i) at a lowest one indexing layer of the indexing layers and (ii) created in response to a respective update for the change journal;
identify one or more first indices of the first plurality of first indices not needed for the change journal, in accordance with a retention policy; and
maintain, using garbage collecting the identified one or more first indices, the change journal of the storage site to track updates to the stored metadata of the plurality of files in a chronological order.