| rjw | 1f88458 | 2022-01-06 17:20:42 +0800 | [diff] [blame^] | 1 | dm-delay |
| 2 | ======== |
| 3 | |
| 4 | Device-Mapper's "delay" target delays reads and/or writes |
| 5 | and maps them to different devices. |
| 6 | |
| 7 | Parameters: |
| 8 | <device> <offset> <delay> [<write_device> <write_offset> <write_delay>] |
| 9 | |
| 10 | With separate write parameters, the first set is only used for reads. |
| 11 | Offsets are specified in sectors. |
| 12 | Delays are specified in milliseconds. |
| 13 | |
| 14 | Example scripts |
| 15 | =============== |
| 16 | [[ |
| 17 | #!/bin/sh |
| 18 | # Create device delaying rw operation for 500ms |
| 19 | echo "0 `blockdev --getsz $1` delay $1 0 500" | dmsetup create delayed |
| 20 | ]] |
| 21 | |
| 22 | [[ |
| 23 | #!/bin/sh |
| 24 | # Create device delaying only write operation for 500ms and |
| 25 | # splitting reads and writes to different devices $1 $2 |
| 26 | echo "0 `blockdev --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed |
| 27 | ]] |