diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2018-04-17 00:33:14 +0200 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2018-07-27 15:24:19 -0400 |
| commit | cda6b5ab7f5935565ed5b9bbc385bd1d0a3feb75 (patch) | |
| tree | f9874d8e3e6d0f6dbefcba98c6835f37694f6009 /Documentation/device-mapper | |
| parent | 3876ac76f02ac2a7b3d96f813c0ee1070e7a8c8e (diff) | |
dm delay: add flush as a third class of IO
Add a new class for dm-delay that delays flush requests. Previously,
flushes were delayed as writes, but it caused problems if the user
needed to create a device with one or a few slow sectors for the purpose
of testing - all flushes would be forwarded to this device and delayed,
and that skews the test results. Fix this by allowing to select 0 delay
for flushes.
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/delay.txt | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/device-mapper/delay.txt b/Documentation/device-mapper/delay.txt index 4b1d22a44ce4..6426c45273cb 100644 --- a/Documentation/device-mapper/delay.txt +++ b/Documentation/device-mapper/delay.txt @@ -5,7 +5,8 @@ Device-Mapper's "delay" target delays reads and/or writes and maps them to different devices. Parameters: - <device> <offset> <delay> [<write_device> <write_offset> <write_delay>] + <device> <offset> <delay> [<write_device> <write_offset> <write_delay> + [<flush_device> <flush_offset> <flush_delay>]] With separate write parameters, the first set is only used for reads. Offsets are specified in sectors. |