[CentOS-mirror] using the --delay-update switch in rsync >= 2.6.4

Thu Sep 15 02:22:29 UTC 2005
Johnny Hughes <mailing-lists at hughesjr.com>

We have upgraded the rsync used on the centos mirrors to a version >=
2.6.4 so that we can use the --delay-updates flag for rsyncing.

This flag (if you have rsync >= 2.6.4) will download all the updates,
then move them into place ... so for items like yum repos, there is a
much shorter time that the repo is not usable during long updates.  If
you have rsync >= 2.6.4, we recommend you use this switch for CentOS
rsyncs.

See the below e-mail for info:


> > >> While a CVS commit is in progress, for instance, other users still see the previous
> > >> state; this is not true for a YUM repository.
> > 
> > >> Hmm.  This sounds like the crux of the problem.  If the mirroring
> > >> software could be tricked into copying the repodata last, wouldn't this
> > >> problem (and this thread) go away?
> > 
> > > rsync does not allow you to specify an order, however rsync has 2 options.
> > > --delay-updates will update the mirror at the end of the sync, which is
> > > near atomic (this is functionality that Jeff Pitman wrote when I needed it
> > > for my repository) and you have an atomic-script that comes with rsync
> > > that hardlinks the tree, makes updates in that new tree and finally
> > > atomically puts it all back.
> > 
> > This one thing right there will help tremendously.  Thanks for the pointer
> > to --delay-updates (any idea which version of rsync this first appeared?).
> 
> OK guys ... the answer is that is was added in version 2.6.4 of
> rsync ... and that is newer than both CentOS-3 and CentOS-4 :(
> 
> BUT - this is such a good feature, we have upgraded the CentOS mirrors
> to have version 2.6.6 of rsync from Dag's repo:
> 
> http://dag.wieers.com/packages/rsync/
> 
> We recommend that if you are rsyncing from centos.org that you get
> the .el3 or .el4 version of rsync (depending on the version of your
> mirror) from above and then add the --delay-updates switch to your rsync
> script when rsyncing from us.
> 
> Many thanks to Dag Wieers for the info on this issue, for submitting the
> request to get this included in rsync ... and for his outstanding repos.


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