Date: Tue, 22 Nov 2022 09:49:29 -0600 From: Mike Karels <mike@karels.net> To: Dan Mack <mack@macktronics.com> Cc: Warner Losh <imp@bsdimp.com>, freebsd-current@freebsd.org Subject: Re: dmesg content lifetime Message-ID: <21FB93B6-708F-4E69-B482-C7601C15394A@karels.net> In-Reply-To: <6146841c-baef-134-dcd9-30db2d92732@macktronics.com> References: <9d519f-ce87-72d-dc6-789817468974@macktronics.com> <CANCZdfq9Q%2BpRBo1HvTDgHcQ6ytMA%2BzZ0DqVx_2E=GoZuBOqWdQ@mail.gmail.com> <6146841c-baef-134-dcd9-30db2d92732@macktronics.com>
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On 22 Nov 2022, at 9:34, Dan Mack wrote: > It disappears a piece at a time - the oldest entries disappear first. H= owever, 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 =E2=80=9Cdmesg -a=E2=80=9D that t= he buffer was full of syslog messages, so dmesg without -a showed nothing. It seems unfortunate that syslog messages logged in the message buffer, a= t least once syslogd is running. Apparently this happens because they are output to /dev/console. Mike > Thank you, > > Dan > > > On Tue, 22 Nov 2022, Warner Losh wrote: > >> On Tue, Nov 22, 2022 at 8:13 AM Dan Mack <mack@macktronics.com> wrote:= >> >>> It seems like dmesg content ages out over time. Is there a way to l= eave >>> 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 >>
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