Root/Documentation/device-mapper/delay.txt

1dm-delay
2========
3
4Device-Mapper's "delay" target delays reads and/or writes
5and maps them to different devices.
6
7Parameters:
8    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]
9
10With separate write parameters, the first set is only used for reads.
11Delays are specified in milliseconds.
12
13Example scripts
14===============
15[[
16#!/bin/sh
17# Create device delaying rw operation for 500ms
18echo "0 `blockdev --getsize $1` delay $1 0 500" | dmsetup create delayed
19]]
20
21[[
22#!/bin/sh
23# Create device delaying only write operation for 500ms and
24# splitting reads and writes to different devices $1 $2
25echo "0 `blockdev --getsize $1` delay $1 0 0 $2 0 500" | dmsetup create delayed
26]]
27

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