US 11,726,663 B2
Dependency resolution for lazy snapshots in storage cluster with delta log based architecture
Vladimir Shveidel, Pardes-Hana (IL); Bar David, Rishon Lezion (IL); and Michael Litvak, Shoham (IL)
Assigned to EMC IP Holding Company LLC, Hopkinton, MA (US)
Filed by EMC IP Holding Company LLC, Hopkinton, MA (US)
Filed on Jan. 13, 2021, as Appl. No. 17/147,740.
Prior Publication US 2022/0221992 A1, Jul. 14, 2022
Int. Cl. G06F 12/08 (2016.01); G06F 12/0808 (2016.01); G06F 12/0815 (2016.01); G06F 3/06 (2006.01)
CPC G06F 3/0619 (2013.01) [G06F 3/067 (2013.01); G06F 3/0653 (2013.01); G06F 3/0659 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of providing dependency resolution for a parent page and a child page in a storage cluster with a delta log-based architecture, comprising:
writing one or more new data values of a parent page to a data log, the new data values of the parent page having corresponding original data values, the new data values of the parent page being written to the data log as respective specialized data entries that maintain both the new data values and the corresponding original data values, and a dependency relationship existing between the parent page and a child page;
in a first de-staging operation for de-staging the parent page to data storage, building the parent page including the new data values maintained by the respective specialized data entries of the data log;
in a second de-staging operation for de-staging the child page to the data storage, building a base page including the original data values of the de-staged parent page maintained by the respective specialized data entries of the data log, and building the child page by applying one or more new data values of the child page to the base page; and
at a time of creation of the dependency relationship between the parent page and the child page, writing, to the data log, a first specialized data entry from among the respective specialized data entries that indicates the child page as being a child of the parent page.