linux/Documentation/device-mapper
Mikulas Patocka 468dfca38b dm integrity: add a bitmap mode
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>
2019-05-08 13:41:58 -04:00
..
cache-policies.txt dm cache: fix grammar in cache-policies.txt 2018-01-17 09:16:07 -05:00
cache.txt dm cache: add support for discard passdown to the origin device 2019-03-05 14:53:52 -05:00
delay.txt dm delay: add flush as a third class of IO 2018-07-27 15:24:19 -04:00
dm-crypt.txt dm crypt: optionally support larger encryption sector size 2017-03-24 15:54:21 -04:00
dm-dust.txt dm: add dust target 2019-04-30 16:37:19 -04:00
dm-flakey.txt dm flakey: Document "error_writes" feature 2018-10-12 11:31:39 -06:00
dm-init.txt dm: add support to directly boot to a mapped device 2019-03-05 14:53:50 -05:00
dm-integrity.txt dm integrity: add a bitmap mode 2019-05-08 13:41:58 -04:00
dm-io.txt
dm-log.txt
dm-queue-length.txt
dm-raid.txt Documentation: Use "while" instead of "whilst" 2018-11-20 09:30:43 -07:00
dm-service-time.txt
dm-uevent.txt
dm-zoned.txt dm zoned: drive-managed zoned block device target 2017-06-19 11:05:20 -04:00
era.txt
kcopyd.txt
linear.txt Documentation/device-mapper: s/getsize/getsz/ 2016-12-14 10:54:27 +01:00
log-writes.txt block: Finish renaming REQ_DISCARD into REQ_OP_DISCARD 2018-10-03 16:12:28 -06:00
persistent-data.txt
snapshot.txt dm snapshot: improve documentation relative to origin suspend requirements 2018-01-17 09:16:06 -05:00
statistics.txt
striped.txt Documentation/device-mapper: s/getsize/getsz/ 2016-12-14 10:54:27 +01:00
switch.txt Documentation/device-mapper: s/getsize/getsz/ 2016-12-14 10:54:27 +01:00
thin-provisioning.txt dm thin: include metadata_low_watermark threshold in pool status 2018-07-30 11:49:08 -04:00
unstriped.txt dm: add unstriped target 2018-01-17 09:16:00 -05:00
verity.txt dm verity: add 'check_at_most_once' option to only validate hashes once 2018-04-03 15:04:29 -04:00
writecache.txt dm writecache: support optional offset for start of device 2018-07-02 16:14:02 -04:00
zero.txt