Re: Intercept write to disk

From: Michael Raskin
Date: Sat May 27 2006 - 03:24:08 EST


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.
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