[dm-devel] Device-mapper for write monitoring

[Alasdair G Kergon]

On Thu, Feb 19, 2009 at 10:06:26AM +0200, Michael Keller wrote:
> For our block-based incremental backup software we need to monitor all
> writes to a device, and report them to our user mode application for
> further processing. 

Sounds like a variant of dm snapshot code.
What precisely do you need?
Notification of every block every time it is changed?
Or just a list of all the blocks that changed within a defined period (i.e.
since the last backup)?

> 3. Are the interfaces of the device mapper relatively stable? (Assume that
> our target is not general enough to be included into mainline, and we'll
> have to do the API chasing ourselves.)

If integrated nicely into dm, it'll go upstream.
 
Alasdair
-- 
agk at redhat.com