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Mikulas Patocka authored
Introduce an alternate mode of operation where dm-integrity uses a bitmap instead of a journal. If a bit in the bitmap is 1, the corresponding region's data and integrity tags are not synchronized - if the machine crashes, the unsynchronized regions will be recalculated. The bitmap mode is faster than the journal mode, because we don't have to write the data twice, but it is also less reliable, because if data corruption happens when the machine crashes, it may not be detected. Benchmark results for an SSD connected to a SATA300 port, when doing large linear writes with dd: buffered I/O: raw device throughput - 245MB/s dm-integrity with journaling - 120MB/s dm-integrity with bitmap - 238MB/s direct I/O with 1MB block size: raw device throughput - 248MB/s dm-integrity with journaling - 123MB/s dm-integrity with bitmap - 223MB/s For more info see dm-integrity in Documentation/device-mapper/ Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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