0001 ========
0002 dm-delay
0003 ========
0004
0005 Device-Mapper's "delay" target delays reads and/or writes
0006 and maps them to different devices.
0007
0008 Parameters::
0009
0010 <device> <offset> <delay> [<write_device> <write_offset> <write_delay>
0011 [<flush_device> <flush_offset> <flush_delay>]]
0012
0013 With separate write parameters, the first set is only used for reads.
0014 Offsets are specified in sectors.
0015 Delays are specified in milliseconds.
0016
0017 Example scripts
0018 ===============
0019
0020 ::
0021
0022 #!/bin/sh
0023 # Create device delaying rw operation for 500ms
0024 echo "0 `blockdev --getsz $1` delay $1 0 500" | dmsetup create delayed
0025
0026 ::
0027
0028 #!/bin/sh
0029 # Create device delaying only write operation for 500ms and
0030 # splitting reads and writes to different devices $1 $2
0031 echo "0 `blockdev --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed
