From owner-freebsd-stable@FreeBSD.ORG Fri May 28 17:57:30 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D4900106568A for ; Fri, 28 May 2010 17:57:30 +0000 (UTC) (envelope-from dave@jetcafe.org) Received: from hugeraid.jetcafe.org (hugeraid.jetcafe.org [205.147.26.109]) by mx1.freebsd.org (Postfix) with ESMTP id 958DE8FC1A for ; Fri, 28 May 2010 17:57:30 +0000 (UTC) Received: from hugeraid.jetcafe.org (localhost [127.0.0.1]) by hugeraid.jetcafe.org (8.13.8/8.13.8) with ESMTP id o4SHvTwq020905; Fri, 28 May 2010 10:57:29 -0700 (PDT) Message-Id: <201005281757.o4SHvTwq020905@hugeraid.jetcafe.org> X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.0.4 To: Clifton Royston In-reply-to: <20100528043006.GA18560@lava.net> References: <201005272348.o4RNmgWh014243@hugeraid.jetcafe.org> <20100528043006.GA18560@lava.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Fri, 28 May 2010 10:57:29 -0700 From: Dave Hayes Cc: freebsd-stable@freebsd.org Subject: Re: Locking a file backed mdconfig into memory 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: Fri, 28 May 2010 17:57:30 -0000 Clifton Royston writes: > It sounds like what you really want is to load the contents of the > specified file as a memory system? That's not part of mdconfig's > repertoire, to the best of my recollection. So if, in /etc/loader.conf, I do this: rootfs_load="YES" rootfs_type="mfs_root" rootfs_name="/mfsboot" vfs.root.mountfrom="ufs:md0" and /mfsboot comes from a bootable DVD, am I to assume that this mount is under the same constraint? Specifically, this constraint is that the /mfsboot file (and hence the DVD) will be read repeatedly if the system is under memory pressure. > If that's what you want, you need to use a different tool; the purpose > of mdconfig is to provide scratch disk. The backing store is to > specify a region its contents can be swapped out to if the system is > under memory pressure (which certainly won't work with a DVD) Heh. Certainly I am using tools for purposes which may not match the original intention. If I wanted to run the rootfs on a memory device which did -not- swap to the backing store of /mfsboot, how would I go about doing that? -- Dave Hayes - Consultant - Altadena CA, USA - dave@jetcafe.org >>> The opinions expressed above are entirely my own <<< Faith (n): The quality by which we believe what we would otherwise think was false.