1======== 2dm-delay 3======== 4 5Device-Mapper's "delay" target delays reads and/or writes 6and maps them to different devices. 7 8Parameters:: 9 10 <device> <offset> <delay> [<write_device> <write_offset> <write_delay> 11 [<flush_device> <flush_offset> <flush_delay>]] 12 13With separate write parameters, the first set is only used for reads. 14Offsets are specified in sectors. 15Delays are specified in milliseconds. 16 17Example scripts 18=============== 19 20:: 21 22 #!/bin/sh 23 # Create device delaying rw operation for 500ms 24 echo "0 `blockdev --getsz $1` delay $1 0 500" | dmsetup create delayed 25 26:: 27 28 #!/bin/sh 29 # Create device delaying only write operation for 500ms and 30 # splitting reads and writes to different devices $1 $2 31 echo "0 `blockdev --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed 32