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Documentation / device-mapper / delay.txt




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Based on kernel version 4.7.2. Page generated on 2016-08-22 22:40 EST.

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