An embodiment of the invention provides a method for creating a snapshot of a data store. A command to create a snapshot of an original data store, stored to a parent virtual logical unit (VLU), is received. A deferred propagation data structure (DPDS) is associated with the parent VLU. The DPDS is capable of containing data propagation records and separators, each data propagation record contains a previous version of one or more data blocks of the parent VLU, each separator contains a pointer to a particular child VLU storing a snapshot of the original data store and separating the data propagation records pertaining to the particular child VLU. A child VLU to store the copy of the original data store is created. A new separator containing a pointer to the child VLU is created in the DPDS. A search pointer pointing to the DPDS is implemented in the child VLU.


> Data processing system

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