From owner-freebsd-current@FreeBSD.ORG Fri Jun 2 07:55:16 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id BBADB16A50A for ; Fri, 2 Jun 2006 07:55:16 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8095743D5A for ; Fri, 2 Jun 2006 07:55:15 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 09A6246D8D; Fri, 2 Jun 2006 03:55:14 -0400 (EDT) Date: Fri, 2 Jun 2006 08:55:13 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Kris Kennaway In-Reply-To: <20060601235740.GA39491@xor.obsecurity.org> Message-ID: <20060602085412.R69345@fledge.watson.org> References: <20060522231437.GC1446@odin.ac.hmc.edu> <20060523133037.GA2908@gothmog.pc> <20060523143013.GA11472@ci0.org> <20060523194106.GA46634@xor.obsecurity.org> <20060524203645.GB13500@gothmog.pc> <20060524203747.GA88742@xor.obsecurity.org> <20060524204617.GA13701@gothmog.pc> <20060601002024.GA1453@gothmog.pc> <20060601210655.GA36389@xor.obsecurity.org> <20060601213527.GA53422@gothmog.pc> <20060601235740.GA39491@xor.obsecurity.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: Giorgos Keramidas , freebsd-current@freebsd.org Subject: Re: md /tmp and async mounts X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 02 Jun 2006 07:55:17 -0000 On Thu, 1 Jun 2006, Kris Kennaway wrote: > On Fri, Jun 02, 2006 at 12:35:27AM +0300, Giorgos Keramidas wrote: > >>> I think it should be the default. I think we should also avoid using -M >>> (malloc backing for md) in favour of swap backing because of the panic >>> problems - this is too easy to trigger by accident and it makes FreeBSD >>> look bad since it looks like a bug. >> >> Ok, I'll prepare a patch that enables async and disables -M. We should >> also document the fact that tmpmfs="YES" and varmfs="YES" in rc.conf may >> require the presence of at least one swap device by default, and point the >> users to -M with a warning if they run FreeBSD without a swap device but >> still want to use tmpmfs or varmfs :) > > Actually I thought about this and don't think it's the case. swap backing > doesn't use swap unless you have memory pressure, and if you have memory > pressure and no swap your system is going to explode regardless. My feeling is that swap-backed md should have been the default years ago. We could add a sanity test to mdconfig that generates a warning if swap-backed md is configured but swapping isn't configured. Robert N M Watson