diff options
author | Mike Snitzer <snitzer@redhat.com> | 2011-08-02 07:32:05 -0400 |
---|---|---|
committer | Alasdair G Kergon <agk@redhat.com> | 2011-08-02 07:32:05 -0400 |
commit | b26f5e3d7127487e934758c1fbe05d683b082cb0 (patch) | |
tree | 8b120e0e45e3a50c1c5adada0eede0870d62457d /Documentation | |
parent | dfd068b01f02653c6650f1c0eda443b2655d1471 (diff) |
dm flakey: add drop_writes
Add 'drop_writes' option to drop writes silently while the
device is 'down'. Reads are not touched.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/device-mapper/dm-flakey.txt | 29 |
1 files changed, 23 insertions, 6 deletions
diff --git a/Documentation/device-mapper/dm-flakey.txt b/Documentation/device-mapper/dm-flakey.txt index c8efdfd19a65..1b66c868ee7e 100644 --- a/Documentation/device-mapper/dm-flakey.txt +++ b/Documentation/device-mapper/dm-flakey.txt | |||
@@ -1,17 +1,34 @@ | |||
1 | dm-flakey | 1 | dm-flakey |
2 | ========= | 2 | ========= |
3 | 3 | ||
4 | This target is the same as the linear target except that it returns I/O | 4 | This target is the same as the linear target except that it exhibits |
5 | errors periodically. It's been found useful in simulating failing | 5 | unreliable behaviour periodically. It's been found useful in simulating |
6 | devices for testing purposes. | 6 | failing devices for testing purposes. |
7 | 7 | ||
8 | Starting from the time the table is loaded, the device is available for | 8 | Starting from the time the table is loaded, the device is available for |
9 | <up interval> seconds, then returns errors for <down interval> seconds, | 9 | <up interval> seconds, then exhibits unreliable behaviour for <down |
10 | and then this cycle repeats. | 10 | interval> seconds, and then this cycle repeats. |
11 | 11 | ||
12 | Parameters: <dev path> <offset> <up interval> <down interval> | 12 | Also, consider using this in combination with the dm-delay target too, |
13 | which can delay reads and writes and/or send them to different | ||
14 | underlying devices. | ||
15 | |||
16 | Table parameters | ||
17 | ---------------- | ||
18 | <dev path> <offset> <up interval> <down interval> \ | ||
19 | [<num_features> [<feature arguments>]] | ||
20 | |||
21 | Mandatory parameters: | ||
13 | <dev path>: Full pathname to the underlying block-device, or a | 22 | <dev path>: Full pathname to the underlying block-device, or a |
14 | "major:minor" device-number. | 23 | "major:minor" device-number. |
15 | <offset>: Starting sector within the device. | 24 | <offset>: Starting sector within the device. |
16 | <up interval>: Number of seconds device is available. | 25 | <up interval>: Number of seconds device is available. |
17 | <down interval>: Number of seconds device returns errors. | 26 | <down interval>: Number of seconds device returns errors. |
27 | |||
28 | Optional feature parameters: | ||
29 | If no feature parameters are present, during the periods of | ||
30 | unreliability, all I/O returns errors. | ||
31 | |||
32 | drop_writes: | ||
33 | All write I/O is silently ignored. | ||
34 | Read I/O is handled correctly. | ||