[leafnode-list] Re: Two (or more) systems synchronization

[Martin <mailinglisten@xxxxxxxxxxxxxxxx>]

Am 07.10.2007 schrieb Reiner Steib:
> On Sat, Oct 06 2007, Martin wrote:
> 
> > If I remember correctly, there's some solution with INN.
> 
> I also heard about this INN feature.  It would be nice to have such a
> feature in leafnode, i.e. fetch articles from a remote newsserver and
> keep the articles as on the server.  This scenario seems to be quite
> common.  It would probably require that there's only a single server
> (the "master") in the "slave's" leafnode setup.

I do not think, that this is a good idea, as long as you do not have
the master under your own control.

Every "big" server now and then renumbers its articles. Whenever this
is the case, and your slave depends and relies on the article numbers
on the master, you have to re-pull the complete spool. Another problem
could be the automatic detection. 

But having a master and a slave leafnode site, things are quite easy.
You and the original poster found a way. 

Maybe, there could be a little more support (syncing between two
leafnodes directly without rsync or something, maybe more UUCP-like),
especially when Matthias decides to change the spool-format. But you
should not be able to run leafnode in slave-mode, when *YOU* do not
control the master.

> Caveats:
> 
> - Exclude out.going and failed.posting from rsync when doing the
>   master -> slave sync.  Instead, you need to sync out.going from
>   slave to master when online (and run fetchnews -P on the master).

Thanks for this hint. I suggested to the OP (accidentally by mail)
postponing and keeping tin-files in sync. Your way is even better.

> - Matthias doesn't want to guarantee that the spool layout stays at it
>   is (traditional news spool: one directory per group, one file per
>   article, overview files) in leafnode2.  So this setup might break in
>   future versions of leafnode(2).

I'd say, this should not keep you from syncing your two computers. In
the worst case, there is a large file. In the very worst case, there
aren't pointers to Byte X and Byte Y in this file, but to inode Z on
your hard disk. 

1) There should be a program then to rebuild the pointers-database.
This could take some time on your laptop, if you just copied the
database and rebuild your pointers - but you'd get things up and
running again.

2) Create a file with 10 MB or something, mount it with 'mount -o
loop /mnt/data/largefile /var/spool/news'. Then shut down leafnode and
unmount. Copy /mnt/data/largefile and mount it on your laptop. Since
you own the connection and maybe have an ethernet cable, this could take
some seconds, but should be quick enough.

All these thoughts do not help, if leafnode stores articles in some
foreign areas like a mysql-database. But this seems to me way too
strange somehow.

Have a nice day...

Martin
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