Can GEOM be used to intercept the I/o calls to an existing mounted device?

[Mark Gladman]

On Friday 11 July 2008 05:19:35 Ivan Voras wrote:
> Tapan Chaudhari wrote:
> > Can't I do it on the fly while the device is already mounted? I just want
> > that all the calls going to the device "/dev/md0s1" first come to me and
> > then it goes to the original device. In short intercepting the i/o calls.
> > Is there some way I can achieve this?
>
> It would be very nice if GEOM could do this, since it would then
> trivially allow things like data replication, log/rollback, etc. but it
> doesn't work like that. In short, no, you cannot listen to IO between
> providers.
>
> (not that it isn't possible to do at all, it just isn't implemented).

Whoops - I was *totally* focussing on the wrong part of his question...
(It was late, that's my excuse. :)