rsync - Mar 2006 - Using rsync to syncronize two unmounted disk partitions

Hi everybody,

I have been using rsync for quite some time, and I've realized it is a
fantastic tool. As it is able to syncronize two CD images, I was
wondering, if I could do that with a harddisk partition. Would it be
possible to syncronize two partitions at device level somehow?

I mean using:
    # rsync /dev/hda8 /dev/hda9
    skipping non-regular file "hda8"

where /dev/hda8 and /dev/hda9 are two unmounted and identical size
partitions on harddisk:
   hda8         Logical   Linux ext3       [/]          501.75
   hda9         Logical   Linux                         501.75


PD. Sorry, I have just seen that Dan Pritts asked a similar question in 
the thread "rsync a raw device". This question stills unanswered
anyway.
-- 
All the best,
   Antonio Arauzo Azofra

On Thu, Mar 16, 2006 at 09:34:43AM +0100, Antonio Arauzo Azofra
wrote:
> Would it be possible to syncronize two partitions at device level
> somehow?
I wonder if someone has written a simple filesystem driver which mounts
the raw data of a device as though it were a single, big file?  Such a
solution would allow the use of any normal filesystem tool (including
rsync) on block-device data.
>    # rsync /dev/hda8 /dev/hda9
Using rsync to update the data for two local block devices wouldn't be
very useful because the incremental-update algorithm would tend to slow
down the transfer instead of speed it up (the only exception for a local
transfer is when the write speed for a device is much slower than the
read speed, and enough of the data matches that the saved write time
more than makes up for the extra read time).

..wayne..