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========
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>
[<flush_device> <flush_offset> <flush_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 --getsz $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 --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed
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