From owner-freebsd-arch@FreeBSD.ORG Tue Aug 24 05:52:18 2010 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 738AF1065679 for ; Tue, 24 Aug 2010 05:52:18 +0000 (UTC) (envelope-from bakul@bitblocks.com) Received: from mail.bitblocks.com (bitblocks.com [64.142.15.60]) by mx1.freebsd.org (Postfix) with ESMTP id 563CA8FC15 for ; Tue, 24 Aug 2010 05:52:18 +0000 (UTC) Received: from bitblocks.com (localhost.bitblocks.com [127.0.0.1]) by mail.bitblocks.com (Postfix) with ESMTP id D0CF25B56; Mon, 23 Aug 2010 22:52:17 -0700 (PDT) To: Matthew Jacob In-reply-to: Your message of "Mon, 23 Aug 2010 21:37:38 PDT." <4C734C92.4010105@feral.com> References: <20100823.171201.107001114053031707.imp@bsdimp.com> <8C76250B-E272-4807-BD0D-9F50D0BC5E10@mac.com> <20100824002350.042A45B3B@mail.bitblocks.com> <4CB9F7C8-39E8-4C3B-A3F8-A5A9EC178E7D@mac.com> <20100824043344.CA4DE5B56@mail.bitblocks.com> <4C734C92.4010105@feral.com> Comments: In-reply-to Matthew Jacob message dated "Mon, 23 Aug 2010 21:37:38 -0700." Date: Mon, 23 Aug 2010 22:52:17 -0700 From: Bakul Shah Message-Id: <20100824055217.D0CF25B56@mail.bitblocks.com> Cc: freebsd-arch@freebsd.org Subject: Re: RFC: enhancing the root mount logic X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Aug 2010 05:52:18 -0000 On Mon, 23 Aug 2010 21:37:38 PDT Matthew Jacob wrote: > Yes, this is the RedHat root pivot goop that's been around for ages. > > It turns out to be a massive PITA, because the initrd image can get out > of sync with the kernel and hardware, and since some of the modules can > be loaded from there, but not from the root filesystem there is a > definite possibility (which has happened with more times than I care to > remember) that you'll get hosed and not be able to mount your root > filesystem. To avoid getting out of sync is why I was advocating bundling the ramfs root with the kernel. That too can have problems -- it is all matter of which compromise you can live with. > This actually can happen so easily that when I install CentOS or Fedora, > I override the defaults and put the root filesystem on a plain > partition/filesystem rather than as part of an LVM2 volume. > > > BTW, a friend tells me this is what Linux does (or more > > likely, what they used in their server startup). Basically a > > ramdisk with init + loadable drivers + tools needed to get > > going. Once the actual root fs device is found (even if > > disks got switched around etc.) they switched to the actual > > root.