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

[Ivan Voras]

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).

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