Object-level replication of cloned objects in a data storage system

A method for replicating file system objects including snapshot-file objects and clone objects from a source file system to a target file system in a data storage system, the method comprises:

• creating a read-only snapshot-file object in the source file system that is associated with a first plurality of blocks that store data and are associated with a plurality of checkpoint numbers;
• creating a first clone object in the source file system that is associated with at least the first plurality of blocks associated with the read-only snapshot file object;
• creating a cloned-in-checkpoint number for the first clone object;
• replicating the read-only snapshot-file object from the source file system to the target file system to create a replicated snapshot-file object;
• creating a second clone object sharing associated blocks with the replicated snapshot-file object in the target file system;
• and
• upon modification of the first clone object in the source file system resulting in an association between the first clone object and at least one diverged block, wherein the at least one diverged block corresponds to a new block or a modified block of the first plurality of blocks;
• creating a new checkpoint number corresponding to the at least one diverged block and replicating the at least one diverged block associated with the first clone object from the source file system to the target file system,
• wherein replicating the at least one diverged block associated with the first clone object from the source file system to the target file system comprises:
• detecting at least one block of the first clone object in the source file system which has changed since creation of the first clone object in the source file system based on comparing checkpoint numbers which are associated with blocks of the first clone object in the source file system with the cloned-in-checkpoint number of the first clone object in the source file system;
• transferring, from the source file system to the target file system, blocks having a checkpoint number higher than or equal to the cloned-in-checkpoint number of the first clone object in the source file system;
• and
• updating the second clone object in the target file system based on blocks received from the source file system so that the second clone object associates with the replicated at least one diverged block in addition to the blocks associated with the replicated snapshot-file object.

A data storage system for replicating file system objects, including snapshot-file objects and clone objects, from a source file system to a target file system, the system including one or more file servers comprising at least one processor configured to execute:

• creating a read-only snapshot-file object in the source file system that is associated with a first plurality of blocks that store data and are associated with a plurality of checkpoint numbers;
• creating a first clone object in the source file system that is associated with at least the first plurality of blocks associated with the read-only snapshot file object;
• creating a cloned-in-checkpoint number for the first clone object;
• replicating the read-only snapshot-file object from the source file system to the target file system to create a replicated snapshot-file object;
• creating a second clone object sharing associated blocks with the replicated snapshot-file object in the target file system;
• and
• upon modification of the first clone object in the source file system resulting in an association between the first clone object and at least one diverged block, wherein the at least one diverged block corresponds to a new block or a modified block of the first plurality of blocks;
• creating a new checkpoint number corresponding to the at least one diverged block and replicating the at least one diverged block associated with the first clone object from the source file system to the target file system,
• wherein replicating the at least one diverged block associated with the first clone object from the source file system to the target file system comprises:
• detecting at least one block of the first clone object in the source file system which has changed since creation of the first clone object in the source file system based on comparing checkpoint numbers which are associated with blocks of the first clone object in the source file system with the cloned-in-checkpoint number of the first clone object in the source file system;
• transferring, from the source file system to the target file system, blocks having a checkpoint number higher than or equal to the cloned-in-checkpoint number of the first clone object in the source file system;
• and
• updating the second clone object in the target file system based on blocks received from the source file system so that the second clone object associates with the replicated at least one diverged block in addition to the blocks associated with the replicated snapshot-file object.