From owner-freebsd-questions Mon Feb 4 22:46:11 2002 Delivered-To: freebsd-questions@freebsd.org Received: from guru.mired.org (dsl-64-192-6-133.telocity.com [64.192.6.133]) by hub.freebsd.org (Postfix) with SMTP id 7B1C537B421 for ; Mon, 4 Feb 2002 22:46:08 -0800 (PST) Received: (qmail 2007 invoked by uid 100); 5 Feb 2002 06:46:06 -0000 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15455.32686.88737.631037@guru.mired.org> Date: Tue, 5 Feb 2002 00:46:06 -0600 To: Alan Eldridge Cc: questions@freebsd.org Subject: Re: ATA_STATIC_IDS In-Reply-To: <91010086@toto.iv> X-Mailer: VM 6.90 under 21.1 (patch 14) "Cuyahoga Valley" XEmacs Lucid X-face: "5Mnwy%?j>IIV\)A=):rjWL~NB2aH[}Yq8Z=u~vJ`"(,&SiLvbbz2W`;h9L,Yg`+vb1>RG% *h+%X^n0EZd>TM8_IB;a8F?(Fb"lw'IgCoyM.[Lg#r\ From: "Mike Meyer" X-Delivery-Agent: TMDA/0.44 (Python 2.2; freebsd-4.5-STABLE-i386) Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG Alan Eldridge types: > Can anybody explain what the practical impact of not enabling ATA_STATIC_IDS > in the kernel is? > > E.g., with static ids I have my / on ad4s1a. If I don't enable ATA_STATIC_IDS, > when I go to reboot the system, do I get an unbootable system, or one that just > can't fsck or mount anything once it boots? (I'd guess the answer is "yes"...) The answer is "it depends". If ATA_STATIC_IDS is enabled, the drives are numbered so that 0 is the primary master, 1 is the primary slave, 2 is the secondary master, 3 is the secondary slave, and so on. Hmmm. Just how many IDE controllers do you have, anyway? If you disable ATA_STATIC_IDS, then it will search for drives in that order, and assign them numbers sequentially as they are found. For instance, if you have three drives now - one master on each of three IDE controller, so that ad4s1a is the one on the third controller, and disable ATA_STATIC_IDS, it's going to turn into ad2s1a. ad0 will be where it used to be, and what was ad2 will now be ad1. The syste may still boot to single user, but it's liable to be confused about where the root is, and fstab is liable to need fixing. Having watched someone add a drive to a system that did dynamic numbering and have it swap to /usr while Ingres was looking for it's raw disk partition on /home was not amusing. http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message