Data syncing in a distributed system

A method comprising:

• maintaining a data structure indicative of a subset of data blocks that have been written to a replicated volume of a storage system during synchronization of the data blocks from a source volume of the storage system to the replicated volume;
• comparing first metadata with second metadata to determine changes in content of the data blocks of the source volume between a first point-in-time and a second point-in-time, wherein the first metadata is a first hash tree having block identifiers indicating the content of the data blocks of the source volume at the first point-in-time and the second metadata is a second hash tree having the blocks identifiers indicating the content of the data blocks of the source volume at the second point-in-time, wherein the first point-in-time is prior to the second point-in-time;
• and
• for each data block of the source volume determined to have changed based upon comparison of the first and second hash trees, updating the replicated volume with the data block when the data structure indicates the data block has not been written to the replicated volume during the synchronization.

The method of 10, wherein each of the first hash tree and the second hash tree further comprises:

• a plurality of leaf nodes (leaves) configured to store the block identifiers;
• two or more internal nodes, each internal node coupled to two or more of the leaves and configured to store a first hash value of the block identifiers of the two or more leaves;
• and
• a root node coupled to the two or more internal nodes and configured to store a second hash value of the first hash values of the two or more internal nodes.

A non-transitory computer-readable medium embodying a set of instructions, which when executed by a processor of a storage system, causes the storage system to:

• maintain a data structure indicative of a subset of data blocks that have been written to a replicated volume of the storage system during synchronization of the data blocks from a source volume of the storage system to the replicated volume;
• compare first metadata with second metadata to determine changes in content of the data blocks of the source volume between a first point-in-time and a second point-in-time, wherein the first metadata is a first hash tree having block identifiers indicating the content of the data blocks of the source volume at the first point-in-time and the second metadata is a second hash tree having the blocks identifiers indicating the content of the data blocks of the source volume at the second point-in-time, wherein the first point-in-time is prior to the second point-in-time;
• and
• for each data block of the source volume determined to have changed based upon comparison of the first and second hash trees, update the replicated volume with the data block when the data structure indicates the data block has not been written to the replicated volume during the synchronization.