From owner-freebsd-questions Mon Mar 24 10:46: 4 2003 Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9249537B401 for ; Mon, 24 Mar 2003 10:45:56 -0800 (PST) Received: from aeimail.aei.ca (aeimail.aei.ca [206.123.6.14]) by mx1.FreeBSD.org (Postfix) with ESMTP id A287343F93 for ; Mon, 24 Mar 2003 10:45:55 -0800 (PST) (envelope-from anarcat@anarcat.ath.cx) Received: from shall.anarcat.ath.cx (idzo03wuu0gi4jd4@dsl-133-253.aei.ca [66.36.133.253]) by aeimail.aei.ca (8.11.6/8.10.1) with ESMTP id h2OIjsN22735; Mon, 24 Mar 2003 13:45:54 -0500 (EST) Received: from lenny.anarcat.ath.cx (lenny.anarcat.ath.cx [192.168.0.4]) by shall.anarcat.ath.cx (Postfix) with SMTP id ED528244; Mon, 24 Mar 2003 13:45:53 -0500 (EST) Received: by lenny.anarcat.ath.cx (sSMTP sendmail emulation); Mon, 24 Mar 2003 13:45:55 -0500 Date: Mon, 24 Mar 2003 13:45:55 -0500 From: The Anarcat To: Mike Meyer Cc: freebsd-questions@freebsd.org Subject: Re: crashdumping on massive amounts of RAM Message-ID: <20030324184555.GD831@lenny.anarcat.ath.cx> Mail-Followup-To: The Anarcat , Mike Meyer , freebsd-questions@freebsd.org References: <20030324174332.GB831@lenny.anarcat.ath.cx> <15999.18326.297880.599596@guru.mired.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="hoZxPH4CaxYzWscb" Content-Disposition: inline In-Reply-To: <15999.18326.297880.599596@guru.mired.org> User-Agent: Mutt/1.5.3i X-Spam-Status: No, hits=-25.5 required=5.0 tests=AWL,EMAIL_ATTRIBUTION,IN_REP_TO,PGP_SIGNATURE_2, QUOTED_EMAIL_TEXT,REFERENCES,REPLY_WITH_QUOTES, USER_AGENT_MUTT autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG --hoZxPH4CaxYzWscb Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon Mar 24, 2003 at 11:59:50AM -0600, Mike Meyer wrote: > In <20030324174332.GB831@lenny.anarcat.ath.cx>, The Anarcat typed: > > I am fortunate enough to have a box with a lot (by my standards) of > > RAM: > >=20 > > real memory =3D 1207877632 (1151 MB) > > avail memory =3D 1166782464 (1112 MB) > >=20 > > Now the problem I have is I'd like to debug the panic()s I'm seeing > > now and then on this box, since I'm running 5.0. :) But it seems I > > need at least as much swap as I need RAM to do this. > >=20 > > So I just want to make sure there is no other way to crashdump this > > RAM than making a gigantic 1GB swap area. The worst is that I really > > don't need 1GB of *swap*!! 1GB of RAM is fine. All processes run in > > main memory, but 1GB of swap? That would *suck*. ;) I have 250MB right > > now and I already think it's too much. > >=20 > > Any brilliant ideas to work around this? >=20 > Yes - enable the kernel debugging option (DDB) on the kernel, and > debug the running system when it panics. The only problem I see with that is with non-reproducable panics, if I don't debug *everything* properly the first time, I might not be able to get back all the data I need. Also, what usually happens is that the victim sends a basic backtrace and a developper then asks to print *b or something like that, which is not possible once the panic is over. :) > As for your swap partition - the same thing happens when you run out > of virtual memory either way: processes start dieing. Having a little > swap lets you get a warning of that because you'll start paging things > out which would otherwise live in memory. Unless you're planning on > setting up a warning system that watches for paging activity and > notifies you so you can do something about it, there's probably not > much point in having 250MB of swap on a system with a gigabyte of > ram. In your shoes, I'd seriously consider running without swap. I've considered it, but I found that I've been able to run over 1GB of mem, so the 250MB is handy to handle exceptional situations as the disk slows down allocation. > On the other hand, disk space is so cheap that I always have lots of > swap. Something about the days when I used to recompile LISP systems > on memory-starved machines.... Eh. It's a 40GB disk and I really considered putting 1GB of it for swap. A. --=20 Nothing incites to money-crimes like great poverty or great wealth. - Mark Twain --hoZxPH4CaxYzWscb Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (FreeBSD) iD8DBQE+f1JjttcWHAnWiGcRAmFMAJ4yDs1rLJTbS475RlRP8hJkiVODsgCgitXC g96rid3ABtNZzzH1GgAtSDE= =0T+L -----END PGP SIGNATURE----- --hoZxPH4CaxYzWscb-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message