Virtual machine disk image backup using block allocation area

摘要

The invention relates to a method for managing virtual machine image disk usage comprising a disk image emulator for a virtual machine provided by a hypervisor, comprising the steps of providing at least a first disk image comprising a sequence of data blocks for accumulating write operations to the first disk image, providing at least a second disk image comprising a sequence of data blocks for permanently storing disk image data, and providing a disk cleaning process for transferring disk image data from the first disk image to the second disk image and deleting unused data blocks in the first and/or the second disk image.

主权项

1. A method for managing virtual machine image disk usage comprising a disk image emulator (22) for a virtual machine (20) provided by a hypervisor (30), comprising the steps of:
providing at least a first disk image (26) comprising a sequence of data blocks for accumulating write operations to the first disk image (26); providing at least a second disk image (28) comprising a sequence of data blocks for permanently storing disk image data; and providing a disk cleaning process (24) for transferring disk image data from the first disk image (26) to the second disk image (28) and deleting unused data blocks in the first and/or the second disk image (26, 28); wherein the disk cleaning process (24) in an initialization phase comprises the steps of:
identifying at least a file system managing the first disk image (26) and the second disk image (28);for each used data block in the first disk image (26),
copying the used data block to the second disk image (28);updating a reference of this used data block in the first disk image (26);for each data block in the first disk image (26) being still used,
copying the data block to a block allocation area in the second image;updating a reference of this data block in the first disk image (26);if the block allocation area of the first image does not contain any further used data blocks, freeing the rest of the block allocation area.