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. 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 ]]