Can rsync update files in place?

[Paul Slootman]

On Tue 16 Apr 2002, Martin Pool wrote:
> On 16 Apr 2002, Paul Slootman <paul+rsync at wurtel.net> wrote:
> 
> > Is there a way to get rsync to not create a new file while transferring
> > and then rename it, but to instead update the existing file in place,
> > i.e. simply write those blocks that have been updated and leave the rest
> > alone?
> 
> That would be pretty hard, though not impossible.
> 
> I suspect it would be roughly as hard to put it into rsync as to 
> write a new program from scratch, depending on what features you need.

That's what I've been thinking :-)

> NetApp machines are kind of a special case because you can't (?)
> run an rsync program directly on the server.  So every block 
> is going across the network in at least one direction.

That's not really a worry, as my goal here is to minimize the number of
writes, not the network traffic.

> Perhaps Oracle's native replication features would be better?

Hmm, in theory perhaps, but not for what I want, which is to regularly
restore the database so that subsequent application tests are performed
on a "known-good' data set. This means running a number of apps against
the database, shutting down the database, restoring the files from
backup, rinse&repeat. And this currently plays havoc with the snapshot
space...


Thanks,
Paul Slootman