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Re: If Linux Is About Choice, Why Then ...

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On Fri, Apr 14, 2017 at 11:40:29AM +0200, Nicolas George wrote:
> Le quintidi 25 germinal, an CCXXV, tomas@xxxxxxxxxx a écrit :
> > You keep repeating this misconception. "Could be" "nobody would". By your
> > logic, Apache and PostgreSQL (among many following this model) wouldn't
> > work. They do. Pretty reliably, at that.
> I am sorry, but you are mistaken here, possibly because you have only a
> vague idea of what "monitoring system" is exactly about.

Thanks for you nice, condescending tone. Very much appreciated.

> You see, when people talk about "monitoring systems", they are not after
> "pretty" reliable, they are after PERFECTLY reliable. They want
> reliability even against million-to-one coincidences.

Your condescending tone doesn't really help in keepig a good discussion.

Besides, PERFECTLY, oh, well. ECC RAM. Redundant processors. Formally
validated software.

> (With the default kernel configuration, "being killed due to a stale PID
> file" is a 1/65535 coincidence, much higher than million-to-one, except
> in Discworld logic.)

I never said SysV's PID scheme is a good idea. For me it's "good enough",
but I mentioned enough alternatives. You have to make sure that the
monitor process doesn't die (modulo things which can happen to PID 1
too), and that's pretty feasible whithin a current Linux system (the
OOM killer you mention, for example: PostgreSQL excludes its postmaster
from that; you've to make sure that the monitor process doesn't get
out of control, but that's achieved by keeping it simple and small).


> And I can say that it happened to me: I have, not often but not just
> once either, found that Apache or another daemon was not running, and
> could not find the reason easily.
> If you are still not convinced, look at the other serious monitoring
> systems: all of them have at least a provision to run as PID 1.

For you, systemd might be the knee's bees: for me it's not, and I think
I've stated my reasons enough. I think we've reached the end of a
productive discussion now.

- -- tomás
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