From owner-freebsd-stable@FreeBSD.ORG Mon Oct 10 13:47:45 2005 Return-Path: X-Original-To: stable@freebsd.org Delivered-To: freebsd-stable@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0EBB116A41F for ; Mon, 10 Oct 2005 13:47:45 +0000 (GMT) (envelope-from freebsd-stable-local@be-well.ilk.org) Received: from mail27.sea5.speakeasy.net (mail27.sea5.speakeasy.net [69.17.117.29]) by mx1.FreeBSD.org (Postfix) with ESMTP id B051F43D48 for ; Mon, 10 Oct 2005 13:47:44 +0000 (GMT) (envelope-from freebsd-stable-local@be-well.ilk.org) Received: (qmail 29236 invoked from network); 10 Oct 2005 13:47:43 -0000 Received: from dsl092-078-145.bos1.dsl.speakeasy.net (HELO be-well.ilk.org) ([66.92.78.145]) (envelope-sender ) by mail27.sea5.speakeasy.net (qmail-ldap-1.03) with SMTP for ; 10 Oct 2005 13:47:43 -0000 Received: by be-well.ilk.org (Postfix, from userid 1147) id 99BEB2F; Mon, 10 Oct 2005 09:47:42 -0400 (EDT) Sender: lowell@be-well.ilk.org To: stable@freebsd.org References: <20051010020729.GA56351@bunrab.catwhisker.org> From: Lowell Gilbert Date: 10 Oct 2005 09:47:41 -0400 In-Reply-To: <20051010020729.GA56351@bunrab.catwhisker.org> Message-ID: <44r7atwkjm.fsf@be-well.ilk.org> Lines: 58 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Subject: Re: 5.x: how do I get a *swap*-backed /tmp via rc.conf? X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Oct 2005 13:47:45 -0000 David Wolfskill writes: > I made the somewhat unexpected discovery that in FreeeBSD 5-STABLE, > if I use the "tmp*" variables in /etc/rc.conf to have an MFS /tmp > created, it is apparentyly not swap-backed -- as I expected from > the part of the mdmfs man page that reads: > > By default, mdmfs creates a swap-based (MD_SWAP) disk with soft-updates > enabled and mounts it on mount-point. > > and a review of the way mdmfs is invoked by /etc/rc; rather, it appears > to be malloc-backed. > > Here's what's in /etc/{defaults/,}rc.conf about it on one such machine: > > g1-59(5.4-S)[42] grep tmp /etc/{default*/,}rc.conf > /etc/defaults/rc.conf:tmpmfs="AUTO" # Set to YES to always create an mfs /tmp, NO to never > /etc/defaults/rc.conf:tmpsize="20m" # Size of mfs /tmp if created > /etc/defaults/rc.conf:tmpmfs_flags="-S" # Extra mdmfs options for the mfs /tmp > /etc/defaults/rc.conf:isdn_traceflags="-f /var/tmp/isdntrace0" # Flags for isdntrace > /etc/defaults/rc.conf:clear_tmp_enable="NO" # Clear /tmp at startup. > /etc/rc.conf:tmpmfs="YES" > /etc/rc.conf:tmpsize="512m" > /etc/rc.conf:tmpmfs_flags="-i4096" > g1-59(5.4-S)[43] > > And: > > g1-59(5.4-S)[43] sudo mdconfig -l -u md0 > md0 malloc 524288 KBytes > g1-59(5.4-S)[44] > > Oh, for some sense of what we're working with: > > g1-59(5.4-S)[44] uname -a > FreeBSD g1-59.catwhisker.org. 5.4-STABLE FreeBSD 5.4-STABLE #6: Sun Oct 9 06:24:17 PDT 2005 root@g1-59.catwhisker.org.:/usr/obj/usr/src/sys/LAPTOP i386 > g1-59(5.4-S)[45] > > So, back to my original question: how do I get a *swap*-backed /tmp? > > [The way I was alerted to the possibliity that my /tmp might not > be swap-backed is that I was using a machine running 5-STABLE as a CVS > server, in order to update /usr/ports on another machine. That's why I > have the -i4096 argument in there, BTW: to double the number of inodes > for when the CVS server starts consuming them with wild abandon as it > builds an isomorphic hierarchy to /usr/ports in /tmp. I think it only > took me 3 panics before I poked around in the mailing list archives and > noted scottl's comment about using a swap-backed /tmp instead, which got > me wondering what backing store my /tmp was using. I did look at > /etc/rc.d/tmp, as well a /etc/rc.subr, but I'm still failing to see why > I'm getting a malloc-backed /tmp. FWIW, although the /tmp in question > is an MFS in 4.x, I do this (use the box as a CVS server for /usr/ports) > without problem on 4.x.] It's hard-coded into rc_subr. Changing it to a default parameter and overriding it in rc.conf would probably be easy to get committed.