Re: Intercept write to disk

[Michael Raskin <a1d23ab4@mail.ru>]

Mishael A Sibiryakov wrote:
> Hm, i need a somthing transparent, this tool is for make image of entire
> disk/partition on fly. Because tool is get some time for work i need to
> store changes between start and end of the process for append it to
> image. Probably i thinking in wrong way and i need a something else.

Maybe you want to back up a partition as it was at some moment in the 
past (exactly)? Then you have to make a device-mapper-snapshot out of 
it. You  need to install device-mapper module and userspace tools, and 
make the following:  original device is never used directly; instead a 
snapshot-origin mapping is made of it and is always used. When you need 
snapshot, you create a file (on another partition, of course; maybe even 
in the memory if you are sure you will do everything quickly enough), 
make it a loopback device, and make a snapshot out of snapshot-origin 
you have and this loopback for changes rollback. Maybe it is also better 
  to mount -o remount,sync the device for the time of creating snapshot 
device in order to have less problems with consistency. And remount it 
back when you start copying.