[dm-devel] dm-slow , a slow down dm ( dm-error alike )

["David Guyon Martin" <david guyonmartin gmail com>]

Hello,

I'm looking for the same feature as Bernd
(http://www.redhat.com/archives/dm-devel/2006-February/msg00014.html),
for different purpose:
We need to slow down a disk access to be able to monitor some events,
for testing.

There is already a dm-error (faulty.c) to simulate a defective device,
why not a dm-slow for a slow device ?
I have written yet a simple unix filter to slow transfer but it can be
used only in specific cases. In the same way dm-slow would accept a
bandwidth parameter to limit read/write speed. Maybe it could also be
changed after the device setup ( slow down speed, and then resume to
full speed once finished monitoring ).

I thought that making a fork from dm-linear or dm-error would be a
good start, since I'm completly new to kernel devel.
I just wonder if my idea isn't flawed by a misunderstanding of the
general dm framework ?

Do you have any comment on this idea, or some advice ?

Thank you,
David G.M.

PS: this is a text-only repost, previous mail maybe caught by anti-spam