32 lines
795 B
ReStructuredText
32 lines
795 B
ReStructuredText
|
========
|
||
|
|
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>
|
||
|
|
[<flush_device> <flush_offset> <flush_delay>]]
|
||
|
|
|
||
|
|
With separate write parameters, the first set is only used for reads.
|
||
|
|
Offsets are specified in sectors.
|
||
|
|
Delays are specified in milliseconds.
|
||
|
|
|
||
|
|
Example scripts
|
||
|
|
===============
|
||
|
|
|
||
|
|
::
|
||
|
|
|
||
|
|
#!/bin/sh
|
||
|
|
# Create device delaying rw operation for 500ms
|
||
|
|
echo "0 `blockdev --getsz $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 --getsz $1` delay $1 0 0 $2 0 500" | dmsetup create delayed
|