replicating a live directory

Clark webclark at
Wed Apr 2 23:15:50 GMT 2008

Matt McCutchen wrote:
> On Sun, 2008-03-30 at 20:55 +0200, Lasse Kliemann wrote:
>> * Message by -Joao Miguel Ferreira- from Sun 2008-03-30:
>>> We would really like to leave all those important services up but we are
>>> really affraid of producing a corrupted replica...
>> Use filesystem snapshots.
>> Linux supports them via LVM. 
>> Solaris and FreeBSD offer them too.
> It's not clear to me how a filesystem snapshot would solve the problem.
> It guarantees that rsync sees an instantaneous state of the filesystem,
> but that state could still include files that are half-modified by other
> programs.
> Matt
I shut everything down so that it is not "live", do a snapshot, then let
people go again.  It is not perfect, but the snapshot process takes only
a second or two, then people can work for the hours it takes for rsync
to run.

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