On Tue, Nov 22, 2022 at 8:49 AM Mike Karels <m...@karels.net> wrote:
> On 22 Nov 2022, at 9:34, Dan Mack wrote:
>
> > It disappears a piece at a time - the oldest entries disappear first.
> However, it vanishes even when there are only 2-3 lines in it so I didn't
> think capacity was in play as I expected.
> >
> > So for example I might see a rate-limit entry from someone spamming the
> system and then it will usually be gone in a couple days and the buffer is
> completely empty. Similarly if I do something like ifconfig em0 down;
> ifconfig em0 up ; it's logged but disappears after a day or so.
> >
> > I'm looking to see if this is just a cron job or something clearing it
> as it might be user-error on my part. Also this is an older system so
> I'll probably look at it again after I update.
>
> I noticed this too, but discovered with “dmesg -a” that the buffer was full
> of syslog messages, so dmesg without -a showed nothing.
>
> It seems unfortunate that syslog messages logged in the message buffer, at
> least once syslogd is running. Apparently this happens because they are
> output to /dev/console.
>
Output to /dev/console that's not via syslogd goes into this buffer for
syslogd
to harvest and put in log files. IIRC, though, there's also the messages
that
syslogd sends to /dev/console in this buffer as well, which can be
confusing.
I'm not sure what a saner policy would be given both of these use cases.
Warner
Mike
>
> > Thank you,
> >
> > Dan
> >
> >
> > On Tue, 22 Nov 2022, Warner Losh wrote:
> >
> >> On Tue, Nov 22, 2022 at 8:13 AM Dan Mack <m...@macktronics.com> wrote:
> >>
> >>> It seems like dmesg content ages out over time. Is there a way to
> leave
> >>> the contents based on a fixed memory size instead?
> >>>
> >>
> >> It already is a fixed memory size. Do you see it all disappear at once,
> or
> >> over time?
> >>
> >> Warner
> >>
>
