logical volumes alignment

[Matt McCutchen]

On Fri, 2007-12-14 at 12:25 -0500, Ming Zhang wrote:
> On Fri, 2007-12-14 at 16:18 +0100, Marco Strullato wrote:
> > Hi all! I'd like to use rsync to keep aligned physical volumes between
> > linux servers. I know that there are other tools but I really need to
> > use rsync.
> > 
> > I would like to do something as
> > rsync /dev/VG/SourceLogicalVolume
> > root at dest_server:/dev/VG/DestinationLogicalVolume
> 
> rsync does not work on special file like block device i believe.

Clarification: rsync does not write data into device nodes.  Marco, you
could use dd instead:

dd if=/dev/VG/SourceLogicalVolume \
	| ssh root at dest_server dd of=/dev/VG/DestinationLogicalVolume

If you need delta-transfer, you could modify your copy of rsync to
accept a --keep-devices option, or you could use the rdiff command-line
interface to the delta-transfer algorithm (but you will need a temporary
file on the destination because rdiff doesn't have an option to generate
inplace deltas).

Matt