Re: where to sync from?
On Wed, Mar 21, 2007 at 04:24:47PM -0300, Carlos Carvalho wrote:
> >In this particular case, we have a bit of an inconsistency. By assigning the
> >ftp.*.d.o alias, we at Debian want to recognize the quality of a mirror and
> >relay this information to all the users, too.
>
> I was going to raise this issue shortly. I think we could be
> "promoted" to primary status.
>
> There are two issues remaining: pushing and CDs. For now we don't
> mirror the CDs, but we expect to have this done in about two weeks
> (via jigdo only, so that the mirror we sync from doesn't get hit).
>
> The second point is push-mirroring. We have everything set up for it
> (account created, public key installed, script in place, etc.). All
> that's left is to ask another mirror to activate the pushing.
Well, only the second part is really required to be a top-notch primary
mirror; because the CD images are so demanding and yet mostly pointless,
they are not a requirement.
> If we become primary we should sync from ftp-master, no?
Not necessarily, but in your case that would be a good option, because your
continent doesn't have any Push-Primary mirrors yet.
In Europe, we used to have official country mirrors connecting directly to
ftp-master (which is in the US), but later we saw that that was pretty
wasteful and not really worth it, because excessive fetching over the pond
just hogged the server over there and latencies and window sizes prevented
any really significant speedups. So we sacrificed our extra 'slots' at
ftp-master and instead switched to using a relay host (syncproxy.eu.d.o)
which pulls the data out of ftp-master alone, and then distributes it here
at lower latencies, and more equally to all (there are many countries in
Europe, so also many official mirrors to feed). It has worked out reasonably
well, at times even excitingly well.
> Now we sync from ftp.de.debian.org. This is due to the old non-US problem.
> Besides, we have a good link with Europe as well as the US; syncing from
> them hasn't been a problem.
>
> Who and how should we ask to do push mirroring?
Exactly how good is your link with Europe compared to the one with the US?
A common test that I used to run is to run mtr to the destination site and
see if there is anything sticking out; and then run something like
wget -O /dev/null http://<site>/debian/pool/main/k/kde-i18n/kde-i18n_3.5.6.orig.tar.gz
And leave it running until a pattern is established. That particular
file is used simply because it's huge (~300 MB) so you won't run out
of bytes before being able to see a pattern; you can interrupt it
once it stops fluctuating, obviously.
> Generally this is a good idea, though in our particular case it's not
> necessary. We have a gigabit link and are very close to the national
> academic backbone. In the debian mirror we can stand a load an order
> of magnitude higher without problem. The rate of ~400 kB/s you get
> from us is not limited by our site.
BTW, what's your /proc/sys/net/ipv4/tcp_wmem like?
--
2. That which causes joy or happiness.
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