[syslog-ng] Syslog-ng to Pipe question

[SOLIS, ALEX]

Great explanation!

I guess I forgot that a pipe is not a file.  I thought it would just
store the logs until the reader woke up again.  Is the pipe is limited
by system resources or something else?

This explains the dropped stat messages but the fifo is only one
destination.  Why doesn't syslog-ng drop the messages destined for
destination(pipe /foo/fifo/} and continue to send messages to all the
other destinations successfully?  I have evidence to support that some
messages to all destinations are dropped.  Why?

Thanks again Valdis for your most elementary clarification of
FIFO-syslog-ng interaction. :)

Alex



-----Original Message-----
From: syslog-ng-bounces at lists.balabit.hu
[mailto:syslog-ng-bounces at lists.balabit.hu] On Behalf Of
Valdis.Kletnieks at vt.edu
Sent: Thursday, July 20, 2006 9:28 AM
To: Syslog-ng users' and developers' mailing list
Subject: Re: [syslog-ng] Syslog-ng to Pipe question


> My question to the experts of the list is why would syslog-ng start
> dropping messages after a separate program reading syslog-ng's
> destination fifo dies?  Is it just coincidence that my monitoring
> program died at exactly the hour I started getting dropped stats?

<mode silly>
Imagine a cardboard tube, several feet long and several inches in
diameter.
We give one guy a *big* basket of balls, and he starts putting the balls
into
one end of the tube, one by one.  Meanwhile, we have another guy at the
other end, taking balls out one at a time.

Now this second guy decides it's time for a nap, so he stops taking
balls out
and tapes something across the end of the tube so balls won't fall out
accidentally.  Eventually, the tube gets full, and when the guy with the
basket tries to put another ball in, it doesn't fit, and just gets
dropped
on the floor.
</mode>

In other words, there's a limit to how much buffering a pipe with no
reader
will give you before it starts complaining, and yes, it's no coincidence
that
it started dropping messages when the program reading the pipe went
away.

After all, what *else* was it supposed to do with them at that point? ;)

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