atomic transaction set option to rsync

[Dag Wieers]

Hi,

Apparently a change of behaviour from rsync 2.5 to rsync 2.6 affected the 
way I worked. I provide RPM repositories that I mirror using rsync. It is 
important to have the repository meta-data in sync with the data otherwise 
people have errors using Yum or Apt.

In the old days (with older rsyncs) I was able to influence the order in 
which my transaction set was processed by changing the order of 
directories I wanted rsync to mirror, so that the metadata was uploaded 
after most of the data and deletes were done at the end of the 
transaction.

With newer rsyncs, rsync seems to sort the transaction set, so I cannot 
longer use this trick to have the metadata uploaded just after the data in 
the same transaction set.

I was wondering if it was possible and acceptable to have an rsync option 
to update the whole transaction in a atomic (or near-atomic way). This 
will also prevent the current problems when a mirror is rsyncing another 
mirror that is rsyncing itself. Since I have little bandwidth to update 
than most other mirrors, I'm often caught in this secnario.

There are other ways to work around it, either by uploading in different 
steps (which is impractical in my scenario) or by using a staging area 
(which is impossible and impractical for large mirror sites).

An option to atomically sync a transaction set would be a god gift for 
situations like these and probably (if not too much overhead) a behaviour 
most repository mirrors would want by default.

--   dag wieers,  dag at wieers.com,  http://dag.wieers.com/   --
[all I want is a warm bed and a kind word and unlimited power]