1 =========
2 dm-flakey
3 =========
4
5 This target is the same as the linear target e
6 unreliable behaviour periodically. It's been
7 failing devices for testing purposes.
8
9 Starting from the time the table is loaded, th
10 <up interval> seconds, then exhibits unreliabl
11 interval> seconds, and then this cycle repeats
12
13 Also, consider using this in combination with
14 which can delay reads and writes and/or send t
15 underlying devices.
16
17 Table parameters
18 ----------------
19
20 ::
21
22 <dev path> <offset> <up interval> <down inte
23 [<num_features> [<feature arguments>]]
24
25 Mandatory parameters:
26
27 <dev path>:
28 Full pathname to the underlying block-
29 "major:minor" device-number.
30 <offset>:
31 Starting sector within the device.
32 <up interval>:
33 Number of seconds device is available.
34 <down interval>:
35 Number of seconds device returns error
36
37 Optional feature parameters:
38
39 If no feature parameters are present, during
40 unreliability, all I/O returns errors.
41
42 error_reads:
43 All read I/O is failed with an error s
44 Write I/O is handled correctly.
45
46 drop_writes:
47 All write I/O is silently ignored.
48 Read I/O is handled correctly.
49
50 error_writes:
51 All write I/O is failed with an error
52 Read I/O is handled correctly.
53
54 corrupt_bio_byte <Nth_byte> <direction> <val
55 During <down interval>, replace <Nth_b
56 each matching bio with <value>.
57
58 <Nth_byte>:
59 The offset of the byte to replace.
60 Counting starts at 1, to replace the f
61 <direction>:
62 Either 'r' to corrupt reads or 'w' to
63 'w' is incompatible with drop_writes.
64 <value>:
65 The value (from 0-255) to write.
66 <flags>:
67 Perform the replacement only if bio->b
68 selected flags set.
69
70 random_read_corrupt <probability>
71 During <down interval>, replace random
72 with a random value. probability is an
73 0 and 1000000000 meaning 0% to 100% pr
74
75 random_write_corrupt <probability>
76 During <down interval>, replace random
77 with a random value. probability is an
78 0 and 1000000000 meaning 0% to 100% pr
79
80 Examples:
81
82 Replaces the 32nd byte of READ bios with the v
83
84 corrupt_bio_byte 32 r 1 0
85
86 Replaces the 224th byte of REQ_META (=32) bios
87
88 corrupt_bio_byte 224 w 0 32
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