1 ========
2 dm-delay
3 ========
4
5 Device-Mapper's "delay" target delays reads an
6 and/or flushs and optionally maps them to diff
7
8 Arguments::
9
10 <device> <offset> <delay> [<write_device>
11 [<flush_device>
12
13 Table line has to either have 3, 6 or 9 argume
14
15 3: apply offset and delay to read, write and f
16
17 6: apply offset and delay to device, also appl
18 to write and flush operations on optionally
19 optionally different sector offset
20
21 9: same as 6 arguments plus define flush_offse
22 on/with optionally different flush_device/f
23
24 Offsets are specified in sectors.
25
26 Delays are specified in milliseconds.
27
28
29 Example scripts
30 ===============
31
32 ::
33 #!/bin/sh
34 #
35 # Create mapped device named "delayed"
36 #
37 dmsetup create delayed --table "0 `bl
38
39 ::
40 #!/bin/sh
41 #
42 # Create mapped device delaying write
43 # splitting reads to device $1 but wri
44 # to different offsets of 2048 and 409
45 #
46 dmsetup create delayed --table "0 `blo
47
48 ::
49 #!/bin/sh
50 #
51 # Create mapped device delaying reads
52 # onto the same backing device at offs
53 #
54 dmsetup create delayed --table "0 `blo
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