Patent ID: 8224780

Claim:
A method implemented at least in part by a computer, the method comprising: indicating that a first set of updates are to be associated with a first checkpoint; determining to write checkpoint data regarding the first checkpoint to a storage of a file system that uses copy on write to update data of the file system; indicating that any updates that occur subsequent to the first set of updates are to be associated with a subsequent checkpoint; generating write plans for the first set of updates, each write plan indicating at least a planned location on storage for data representing at least one of the first set of updates; updating metadata to indicate allocation data of the file system as well as storage locations for file system objects modified by the write plans; creating a logical copy of the metadata; creating a write plan to write the first checkpoint data while allowing write plans to be generated for the subsequent updates in parallel with creating the write plan: and writing at least one validation code to storage, the at least one validation code part of the checkpoint data, the at least one validation code usable to determine whether the first set of updates was correctly written to storage.