From owner-freebsd-stable@FreeBSD.ORG Mon Oct 10 14:54:52 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 E1A4F16A433 for ; Mon, 10 Oct 2005 14:54:51 +0000 (GMT) (envelope-from malcolm.kay@internode.on.net) Received: from smtp1.adl2.internode.on.net (smtp1.adl2.internode.on.net [203.16.214.181]) by mx1.FreeBSD.org (Postfix) with ESMTP id 65B2543D45 for ; Mon, 10 Oct 2005 14:54:51 +0000 (GMT) (envelope-from malcolm.kay@internode.on.net) Received: from alpha.home (ppp226-206.lns2.adl4.internode.on.net [203.122.226.206]) by smtp1.adl2.internode.on.net (8.12.9/8.12.6) with ESMTP id j9AEsnCZ085321 for ; Tue, 11 Oct 2005 00:24:49 +0930 (CST) (envelope-from malcolm.kay@internode.on.net) From: Malcolm Kay Organization: at home To: stable@freebsd.org Date: Tue, 11 Oct 2005 00:25:34 +0930 User-Agent: KMail/1.8 References: <20051010020729.GA56351@bunrab.catwhisker.org> In-Reply-To: <20051010020729.GA56351@bunrab.catwhisker.org> MIME-Version: 1.0 Content-Disposition: inline Message-Id: <200510110025.34765.malcolm.kay@internode.on.net> Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit 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 14:54:52 -0000 On Mon, 10 Oct 2005 11:37 am, David Wolfskill wrote: > 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] > These paramaters are used by the startup script /etc/rc.d/tmp which calls mount_md defined in /etc/rc.subr which specifically adds the _M (malloc) option to the mdmfs call. You'll need to invoke your own script (or; not so nice; edit rc.subr). Malcolm > 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.] > > (I don't need separate copies of any replies; I read -stable, > so I set Reply-To as an appropriate hint.) > > Thanks. > > Peace, > david