========dm-delay======== Device-Mapper's "delay" target delays reads and/or writesand/or flushes and optionally maps them to different devices. Arguments::     <device> <offset> <delay> [<write_device> <write_offset> <write_delay>			       [<flush_device> <flush_offset> <flush_delay>]] Table line has to either have 3, 6 or 9 arguments: 3: apply offset and delay to read, write and flush operations on device 6: apply offset and delay to device, also apply write_offset and write_delay   to write and flush operations on optionally different write_device with   optionally different sector offset 9: same as 6 arguments plus define flush_offset and flush_delay explicitly   on/with optionally different flush_device/flush_offset. Offsets are specified in sectors. Delays are specified in milliseconds.  Example scripts=============== ::	#!/bin/sh	#	# Create mapped device named "delayed" delaying read, write and flush operations for 500ms.	#	dmsetup create delayed --table  "0 `blockdev --getsz $1` delay $1 0 500" ::	#!/bin/sh	#	# Create mapped device delaying write and flush operations for 400ms and	# splitting reads to device $1 but writes and flushes to different device $2	# to different offsets of 2048 and 4096 sectors respectively.	#	dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 2048 0 $2 4096 400" ::	#!/bin/sh	#	# Create mapped device delaying reads for 50ms, writes for 100ms and flushes for 333ms	# onto the same backing device at offset 0 sectors.	#	dmsetup create delayed --table "0 `blockdev --getsz $1` delay $1 0 50 $2 0 100 $1 0 333"