cronning rsync

[matthew.2.burgess at bt.com]

We're thinking about putting rsync to use in our production environment.
What we want to do is have a cron job running on a client that replicates
files on the host every five minutes.  We believe that some of the files
will take longer than five minutes to complete.  From the limited testing
I've done it looks like the first rsync session correctly identifies the
file as a candidate for transferring.  Five minutes later the second rsync
process is started and it too thinks that the file is out of date (as it
still is) and subsequently starts transferring the file again.  Ideally, the
second process should realise that the file, although being out of date, is
already in the process of being synchronised, and therefore ignore it.  Does
an option exist that handles situations like this (and I've simply
overlooked it) or is my situation general enough to warrant a feature like
the one above being implemented?

Thanks in advance,

Matthew Burgess

British Telecommunications plc
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