swh:1:snp:3c665ee4f67729f27f2e40193ab88e7298cf0fef
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Tip revision: f6161aa153581da4a3867a2d1a7caf4be19b6ec9 authored by Linus Torvalds on 10 March 2013, 23:54:19 UTC
Linux 3.9-rc2
Tip revision: f6161aa
delay.txt
dm-delay
========

Device-Mapper's "delay" target delays reads and/or writes
and maps them to different devices.

Parameters:
    <device> <offset> <delay> [<write_device> <write_offset> <write_delay>]

With separate write parameters, the first set is only used for reads.
Delays are specified in milliseconds.

Example scripts
===============
[[
#!/bin/sh
# Create device delaying rw operation for 500ms
echo "0 `blockdev --getsize $1` delay $1 0 500" | dmsetup create delayed
]]

[[
#!/bin/sh
# Create device delaying only write operation for 500ms and
# splitting reads and writes to different devices $1 $2
echo "0 `blockdev --getsize $1` delay $1 0 0 $2 0 500" | dmsetup create delayed
]]
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