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authorMikulas Patocka <mpatocka@redhat.com>2017-04-18 16:51:52 -0400
committerMike Snitzer <snitzer@redhat.com>2017-04-24 12:04:33 -0400
commit9d609f85b7eb96697ae22ad1d47a3a3920174ba8 (patch)
tree25610e72c2f7eff159c44c6afc8a88d080ee7447 /Documentation/device-mapper
parent56b67a4f292f14548f4046979d46d07bcf8ba971 (diff)
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dm integrity: support larger block sizes
The DM integrity block size can now be 512, 1k, 2k or 4k. Using larger blocks reduces metadata handling overhead. The block size can be configured at table load time using the "block_size:<value>" option; where <value> is expressed in bytes (defult is still 512 bytes). It is safe to use larger block sizes with DM integrity, because the DM integrity journal makes sure that the whole block is updated atomically even if the underlying device doesn't support atomic writes of that size (e.g. 4k block ontop of a 512b device). Depends-on: 2859323e ("block: fix blk_integrity_register to use template's interval_exp if not 0") Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/device-mapper')
-rw-r--r--Documentation/device-mapper/dm-integrity.txt5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/device-mapper/dm-integrity.txt b/Documentation/device-mapper/dm-integrity.txt
index ced34cd915ef..f33e3ade7a09 100644
--- a/Documentation/device-mapper/dm-integrity.txt
+++ b/Documentation/device-mapper/dm-integrity.txt
@@ -136,6 +136,11 @@ journal_mac:algorithm(:key) (the key is optional)
the journal. Thus, modified sector number would be detected at
this stage.
+block_size:number
+ The size of a data block in bytes. The larger the block size the
+ less overhead there is for per-block integrity metadata.
+ Supported values are 512, 1024, 2048 and 4096 bytes. If not
+ specified the default block size is 512 bytes.
The journal mode (D/J), buffer_sectors, journal_watermark, commit_time can
be changed when reloading the target (load an inactive table and swap the