Patent ID: 7100006

Claim:
A method of generating a snapshot of first storage that is logically subdivided into a plurality of blocks, the method comprising: on initiating the snapshot, initially copying to snapshot storage the content of a portion of the first storage that includes at least one block and recording in a copy map a copied indication for each copied block; in response to any write request to a block for which no copied indication has been recorded in the copy map, copying to the snapshot storage the content of the block, prior to writing to it, and recording in the copy map a copied indication for the copied block; and successively copying to the snapshot storage the content of other blocks for which no copied indication has been recorded in the copy map and recording in the copy map a copied indication for each copied block, until the content of the plurality of blocks have been copied to the snapshot storage; wherein the initially copied storage portion includes one or more blocks containing part of an operating system kernel.