US 11,875,060 B2
Replication techniques using a replication log
Vladimir Shveidel, Pardes-Hana (IL); and Vamsi K. Vankamamidi, Hopkinton, MA (US)
Assigned to Dell Products L.P., Hopkinton, MA (US)
Filed by Dell Products L.P., Hopkinton, MA (US)
Filed on Apr. 18, 2022, as Appl. No. 17/722,649.
Prior Publication US 2023/0333777 A1, Oct. 19, 2023
Int. Cl. G06F 12/00 (2006.01); G06F 3/06 (2006.01)
CPC G06F 3/0659 (2013.01) [G06F 3/065 (2013.01); G06F 3/067 (2013.01); G06F 3/0619 (2013.01); G06F 3/0652 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A computer-implemented method comprising:
receiving, at a source system, a first write directed to a source logical device configured for asynchronous remote replication to a target logical device of a destination system;
performing first processing on the source system that flushes a first transaction log entry of a transaction log of the source system, said first processing including:
determining for the first transaction log entry, which represents the first write storing first content to a target logical address, that the first write is directed to the source logical device configured for asynchronous remote replication and that the first content has not been replicated from the source system to the destination system; and
creating a first replication log entry for the first write and the first content in a replication log of the source system, wherein the first replication log entry includes a reference to a first storage location of the first content, wherein the replication log includes entries corresponding to other entries of the transaction log which have been flushed from the transaction log and which represent content and checkpoint commands that have not been replicated from the source system to the destination system; and
performing replication processing that uses a replication queue including a first replication queue entry corresponding to the first write that stores the first content to the target logical address, the replication processing including:
determining, for the first replication queue entry, that the first content written to the target logical address is not in a cache of the source system thereby resulting in a cache miss;
responsive to the cache miss, retrieving the first content from the first storage location using the reference to the first storage location, wherein the reference to the first storage location is obtained from the first replication log entry or the first replication queue entry corresponding to the first write; and
replicating the first content stored at the target logical address by the first written operation from the source system to the destination system.