Patent ID: 9311190
Filing Date: 2016-04-12
CPC Classification: G06F

Claim Text:
1. A method for capturing post-snapshot quiescence writes in a linear image backup chain, the method performed by one or more processors on a source storage, the method comprising: taking a first snapshot of the source storage at a first point in time; identifying a first set of block positions of blocks that are allocated in the source storage at the first point in time; identifying a second set of block positions of blocks that are written to the first snapshot during post-snapshot quiescence of the first snapshot, resulting in a first quiesced snapshot; copying the blocks in the first set of block positions from the first snapshot to a full image backup; copying the blocks in the second set of block positions from the first quiesced snapshot to a first incremental image backup that depends on the full image backup; tracking a third set of block positions of the blocks that are modified in the source storage between the first point in time and a second point in time; taking a second snapshot of the source storage at the second point in time; identifying a fourth set of block positions of the blocks that are allocated in the source storage at the second point in time; identifying a fifth set of block positions of blocks that are written to the second snapshot during post-snapshot quiescence of the second snapshot, resulting in a second quiesced snapshot; calculating a sixth set of block positions by performing a Boolean OR operation on the second set of block positions and the third set of block positions; calculating a seventh set of block positions by performing a Boolean AND operation on the fourth set of block positions and the sixth set of block positions; copying the blocks in the seventh set of block positions from the second snapshot to a second incremental image backup that depends on the first incremental image backup; and copying the blocks in the fifth set of block positions from the second quiesced snapshot to a third incremental image backup that depends on the first incremental image backup.