Patent ID: 8862546
Filing Date: 2014-10-14
Classification: G06F

Abstract:
1. A system for data replication, the system comprising: a first site, the first site comprising a first storage medium, the first storage medium having one or more images of logical storage units; a data protection appliance (DPA); a journal, the journal having DO data and UNDO data; and computer-executable logic operating in memory, wherein the computer-executable program logic is configured for execution of: building a virtual image of a point in time in the DPA; wherein the virtual image corresponds to a virtual copy of a logical storage unit at a first time by: taking a storage array based snapshot of a current image of the one or more images of the storage medium; wherein the current image corresponds to the logical storage unit at a second time and noting what DO data and UNDO data of the journal needs to be applied to the storage array based snapshot to roll the current image from the second time to the first time; exposing a LUN containing the virtual image corresponding to the point in time image at the DPA; wherein the virtual image corresponds to the noted DO data and UNDO data of the journal and the storage array based snapshot; wherein read and write access to the exposed LUN is enabled; wherein write IOs are written to the current image; marking differences between the virtual image and the snapshot of the current image in a protection bitmap; pulling, in the background of the replication, data from the LUN containing virtual image exposed by DPA to the current image of the one or more images of the storage medium; wherein the pulling reads the data from the virtual image and writes it to the current image to roll the current image to the point in time; and in response to receiving a read request to the virtual image: