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author | Heinz Mauelshagen <mauelshagen@redhat.com> | 2007-05-09 02:33:06 -0700 |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-05-09 12:30:47 -0700 |
commit | 26b9f228703f0518a90e7513d6fe7b6abeed5138 (patch) | |
tree | 3437e92667c338ea46ad47b064ce4908d7d75fe2 /Documentation | |
parent | 0ba699347e96b5468b42b3decf1f381abbf99652 (diff) | |
download | kernel_samsung_tuna-26b9f228703f0518a90e7513d6fe7b6abeed5138.zip kernel_samsung_tuna-26b9f228703f0518a90e7513d6fe7b6abeed5138.tar.gz kernel_samsung_tuna-26b9f228703f0518a90e7513d6fe7b6abeed5138.tar.bz2 |
dm: delay target
New device-mapper target that can delay I/O (for testing). Reads can be
separated from writes, redirected to different underlying devices and delayed
by differing amounts of time.
Signed-off-by: Heinz Mauelshagen <mauelshagen@redhat.com>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/device-mapper/delay.txt | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/device-mapper/delay.txt b/Documentation/device-mapper/delay.txt new file mode 100644 index 0000000..15adc55 --- /dev/null +++ b/Documentation/device-mapper/delay.txt @@ -0,0 +1,26 @@ +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 +]] |