swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Raw File
Tip revision: a909d3e636995ba7c349e2ca5dbb528154d4ac30 authored by Linus Torvalds on 29 October 2016, 20:52:02 UTC
Linux 4.9-rc3
Tip revision: a909d3e
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.
Offsets are specified in sectors.
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
]]
back to top