Re: where to sync from?
On Wed, 2007-03-21 at 18:07 +0100, Josip Rodin wrote:
> On Wed, Mar 21, 2007 at 12:07:09PM -0400, Ricardo Yanez wrote:
> > Many years ago, before 2002, we were syncing with ftp.br.debian.org,
> > then one day, the entire debian/ tree was gone with the catastrophic
> > result that our entire tree was deleted as well. It took us weeks to
> > re-build the tree again (yeah, that slow! and debian in those days was a
> > 10th of what is today). Based on this painful experience I've been very
> > reluctant to use leaf mirrors to sync.
>
> ftp.br.d.o had its share of problems in the past, yes, but that was probably
> when it was hosted elsewhere. The alias changed hands a few times by now.
>
> About that particular problem - please use the option --max-delete for
> rsync. Set it to something like 50000, that should be safe enough.
>
> > I mean, ftp.cl.debian.org is a leaf mirror, low in the hierarchy, and
> > should stay there based on it's not-so-hot "stableness". I see
> > ftp.br.debian.org is also a leaf mirror, which I interpret as not being so
> > high in the hierarchy either. Maybe I'm wrong about my interpretation of
> > Leaf, Secondary and Primary mirrors, but these categories must somehow
> > reflect how committed the sponsor and admins are to the mirror, right?
>
> 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.
>
> The mirrors in the western hemisphere are mostly dependent on the Northern
> American mirrors, mainly because ftp-master.debian.org is in the US and the
> layout of the Internet links in general works that way. It would be logical
> for us Debianites to work with mirror admins in both North and South America
> in order to provide the best service; for example, we should organize the
> first tier of push-mirrors and provide assistance with the second tier;
> allowing more mirrors to get pushed so that they can update more
> efficiently.
>
> Yet, we have this bizarre situation where the North American mirrors
> have been continuously either neglected or struggling due to external
> influences, despite the fact that they are actually the closest ones to
> ftp-master.debian.org.
>
> We have the ftp.debian.org which is constantly overloaded, but graciously
> hosted at a university which won't kick us out (at least not yet). It is
> maxing out its 100Mbit connection virtually all the time[1]. We have
> ftp.us.debian.org as a round-robin of three, currently - one is ftp.d.o,
> the other is another mirror at a university, and the third is
> mirrors.kernel.org, hosted by ISC. All of those are generally under a high
> load, because the US users aren't aided in order to spread the load. The
> Canadians either; we used to have a separate ftp.ca.debian.org, but once
> that site went offline, nobody worked to seek a replacement, and instead
> all that load was shifted onto ftp.debian.org. It's been like that for years
> now.
>
> The selection of mirrors in the round-robin is controlled by a few Debian
> admins who aren't particularly interested in improving it, and the selection
> has only shrunk in the last few years (once upon a time, we had six machines
> in it; now we only have three). I have tried to contribute to fixing this
> problem, but was told to butt out, mostly because as a European I didn't
> have enough information about the US matters; I then on a separate occasion
> organized a syncproxy.wna.d.o on the west coast, but that's as far as that
> went (that was needed to fix up the Australian mirrors). On a few occasions
> I contributed a few bits and pieces (such as asking elmo to up
> ftp-master.d.o tcp_wmem so that it does cross-continental syncs faster), but
> the main problem remained unsolved. I later went AWOL and nobody seemed to
> pick up the torch after me. Now I'm a bit more active again, and I see the
> status quo remains; and also I lost my (unprivileged) account on
> ftp-master.d.o so I can't even track the log files over there any more,
> and my requests to have it reinstated are ignored for months.
>
> The secondary mirrors in the US which aren't part of the round-robin alias
> are mostly not pushed, and I guess most people just don't use them. These
> mirrors end up servicing a local community, which was usually the reason
> they were set up; as well as the few people who actually go through the huge
> list and pick a mirror from it.
>
> So, the logical thing to do here would be to get your two mirrors, which
> are the official mirrors for two large countries, pushed from either
> ftp-master.debian.org or from one of the ftp.us.debian.org sites.
> But, I don't have any idea how to do that, because a) nobody cares to do
> these things b) the sites are mostly overloaded anyway so they would
> probably be slow to sync from, unless some special arrangements were made.
>
> I guess that now that I spent time writing this mail, I could have another
> go at trying to find out which debian-admin member now tends after these
> things, and see if anything can be changed.
>
> > In our case, the environment is somewhat hostile, perhaps unforgiven about
> > the needs of a server. For example, over some weekends, people saw the
> > mirror on and turned it off thinking someone must have forgotten it on,
> > because that's what people do with their windows desktops. Today the
> > server is locked up, which only reduces the frequency of these events. Or,
> > someone unplugs a switch to plug an electric kettle. Even more common,
> > power outages lasting days, particularly during weekends when some people
> > think switching off the entire building at the main fuse box helps
> > conserving energy and money. That's the kind of things we have to struggle
> > against, not to mention a Computing Department that seems to be playing
> > around with a filter.
>
> I trust you plan to get it into a proper server room in the future :)
> Many of us have experienced similar problems in the past; I sympathise :/
>
> --
> 2. That which causes joy or happiness.
>
> [1] http://saens.debian.org/mrtg/saens.eth0.html
>
>
I must thank you for such upfront and honest description of things. As
an old-time mirror admin (started 1999) I have felt many times
abandonment and incomprehension from Debian. Debian is still a
non-profit, volunteer-based organization, so I won't judge or complain.
After all, I chose Debian, and committed to it, for that very reason.
It seems to me there is a lot we can do, I mean among ourselves, mirror
admins. I think it's true a lot of mirrors in the mirror list are hardly
used. I myself, knowing first hand how the mirror structure works,
choose without hesitating a ftp.[].debian.org mirror depending on where
I am. Prejudice? perhaps, but I tend to blame it on gut instinct.
Whatever says debian.org gives me instant confidence. Bottom line, there
is a lot of willing bandwidth out there that is not properly used to
balance the load. What if admins of the same country subscribed to this
list joined in effort? Just to pull an example. I just recently, based
on this discussion, payed attention to the Brazil mirror. Looking at the
mirror list, one sees there are seven (7!) mirrors in Brazil. One
immediately wonders why these 7 could not join forces, much like the US
three official mirrors, into one potent rotation of mirrors? Three of
them even come from the same university! See the point? Chile has two
mirrors, our own and debian.ubiobio.cl. Couldn't we do the same as the
ftp.us.debian.org mirrors do? BTW, is the admin of debian.ubiobio.cl
subscribed to this list? Then there wouldn't be any mirrors looked down
upon.
Ricardo Yanez
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