I get a ``panic: cant mount root'' error when rebooting the system after installation.

From owner-freebsd-questions Mon Apr 12 15:33:18 1999 Delivered-To: freebsd-questions@freebsd.org Received: from inet16.us.oracle.com (inet16.us.oracle.com [192.86.155.100]) by hub.freebsd.org (Postfix) with ESMTP id 817B715690 for ; Mon, 12 Apr 1999 15:33:11 -0700 (PDT) (envelope-from rfritz@us.oracle.com) Received: from usmail04 (usmail04.us.oracle.com [144.25.88.96]) by inet16.us.oracle.com (8.8.5/8.8.5) with SMTP id PAA09253 for ; Mon, 12 Apr 1999 15:30:52 -0700 (PDT) Received: from us.oracle.com by usmail04 with ESMTP (SMI-8.6/37.9) id PAA29686; Mon, 12 Apr 1999 15:30:51 -0700 Message-ID: <371274E0.2CB913B4@us.oracle.com> Date: Mon, 12 Apr 1999 18:34:09 -0400 From: Bob Fritz Reply-To: rfritz@us.oracle.com Organization: Oracle Corporation X-Mailer: Mozilla 4.06 [en] (WinNT; U) MIME-Version: 1.0 To: questions@freebsd.org Subject: I get a ``panic: cant mount root'' error when rebooting the system after installation. Content-Type: multipart/mixed; boundary="------------7F2DBBB1CED25216857B92A9" Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG This is a multi-part message in MIME format. --------------7F2DBBB1CED25216857B92A9 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I get this error after installing 3.1 on a dedicated scsi drive. The PC has 1 IDE Drive (bios 0) and 3 scsi drives, scsi id's 0,1 and 2. BSD is installed on scsi id 2. What boot string should I use to boot the OS? Thanks You http://www.freebsd.org/FAQ/FAQ49.html#49 --------------7F2DBBB1CED25216857B92A9 Content-Type: text/html; charset=us-ascii; name="FAQ49.html" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="FAQ49.html" Content-Base: "http://www.freebsd.org/FAQ/FAQ49.html" I get a ``panic: cant mount root'' error when rebooting the system after installation.

Frequently Asked Questions for FreeBSD 2.X : Installation : I get a ``panic: cant mount root'' error when rebooting the system after installation.
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2.25. I get a ``panic: cant mount root'' error when rebooting the system after installation.

This error comes from confusion between the boot block's and the kernel's understanding of the disk devices. The error usually manifests on two-disk IDE systems, with the hard disks arranged as the master or single device on separate IDE controllers, with FreeBSD installed on the secondary IDE controller. The boot blocks think the system is installed on wd1 (the second BIOS disk) while the kernel assigns the first disk on the secondary controller device wd2. After the device probing, the kernel tries to mount what the boot blocks think is the boot disk, wd1, while it is really wd2, and fails.

To fix the problem, do one of the following:

At the Boot: prompt, enter 1:wd(2,a)kernel and press Enter. If the system starts, then run the command
```
echo "1:wd(2,a)kernel" > /boot.config
```
to make it the default boot string.
Move the FreeBSD disk onto the primary IDE controller, so the hard disks are consecutive.

Rebuild your kernel, modify the wd configuration lines to read:

controller      wdc0    at isa? port "IO_WD1" bio irq 14 vector wdintr
disk            wd0     at wdc0 drive 0
# disk            wd1     at wdc0 drive 1 # comment out this line

controller      wdc1    at isa? port "IO_WD2" bio irq 15 vector wdintr
disk            wd1     at wdc1 drive 0 # change from wd2 to wd1
disk            wd2     at wdc1 drive 1 # change from wd3 to wd2

Install the new kernel. If you moved your disks and wish to restore the previous configuration, replace the disks in the desired configuration and reboot. Your system should boot successfully.

freebsd-questions@freebsd.org
Updated April 12, 1999

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