[ZWeb] DNS still fishy?

Lennart Regebro regebro at gmail.com
Thu Oct 12 13:35:00 EDT 2006

On 10/12/06, Justizin <justizin at siggraph.org> wrote:
> Servers failing will not cause problems, the only real risk would be tampering.

I was unclear, sorry.

What I ment to say is that things go wrong. Your statement "this
should not cause problems", is equivalent to "servers will not fail"
and my point then was that in that case we can run with one server and
be done with it.

The reality is that servers fail. The reality is also that complex
setups cause problems, no matter that they "shouldn't".

> The reason for having many servers is to protect against failure.

With increasing number of servers you get better protection against
failure. But the  increasing protection you get gets less and less
with each server. At the same time, configuration weirdness and other
stuff is likely to INCREASE the error rate the more backups you have,
because of Murphys law and other stuff.

At one point, this increase in problems will overwhelm the increase in

I would also like to claim that this crossover point is nowehere near
the previously mentioned number of eight servers, but rather closer
two have one or two backups on another continent.

Some maths:

Say that a server fails one day per month in average (which is way
more than we really will have). One backup server located on anotehr
continent then means that we will statistically have DNS outage only
one day in 900. Thats one day every three years. Two backups located
on different continents will give us a failure rate of one day per
27000 days. That's one day every seventy-fifth year.

How would five-six increasing backup servers in any reasonable way
actually increase that realiability? It wouldn't, because for every
server you add, you increase the risk of something going wrong. That's
probably not an exponential risk, but I'm pretty sure somebody
somewhere will fuck something up more often than every seventy-fifth
year, so I don't actually think that having more than two backups on
different continents is gonna increase realiability.

> "Three or more" is best.

If you talk about total number of DNS servers, then I agree.
Two at zoneedit, one or two more somewhere else.

> Then take over, Lennart.  I do not care.

Oh, you do care, because you get angry-

> You said you don't understand why we don't just use zoneedit.

No. I have never said anything like that. Please read what I say, and
answer that. I have been discussing politics on the internet for 15
years, and one thing I have learned is to completely stop any
discussion when you get accused of an opinion you don't have because
constructive discussion have at that point failed.

Please read my emails, and answer they things I said, not the things I
did not say.

> What makes four servers less failure prone than eight, so long as they
> all agree that zoneedit is in charge.

I think that is a pretty obvious question. The more things you have
the more things will fail.

> Look, I'm sick of this conversation.  I did a better job than anyone
> else in the conversation would have, and problems happened because we
> spent a week on something that we should have spent 2-4 weeks on.  We
> learned something.

That is quite possible. I am not claiming you did a bad job. I have
never said I would do a better job. I don't complain, whine or say you
are stupid. I'm say one simple thing:

Having eight servers is overkill and cause more problems than it solves.

Please discuss this instead of trying to make this be about some sort
of personal issue. It is not. You are a professional.  I am a
professional.  Lets please all behave like it.

Lennart Regebro, Nuxeo     http://www.nuxeo.com/
CPS Content Management     http://www.nuxeo.org/

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