Booting a SPARC Based System in Failsafe Mode

Booting a system from a root file system image that is a boot archive, and then remounting this file system on the actual root device can sometimes result in a boot archive and root file system that do not match, or are inconsistent. Under these conditions, the proper operation and integrity of the system is compromised. After the root (/) file system is mounted, and before relinquishing the in-memory file system, the system performs a consistency verification against the two files systems. If an inconsistency is detected, the normal boot sequence is suspended and the system reverts to failsafe mode.

Also, if a system failure, a power failure, or a kernel panic occurs immediately following a kernel file update, the boot archives and the root (file system might not be synchronized. Although the system might still boot with the inconsistent boot archives, it is recommended that you boot the failsafe archive to update the boot archives. You can also use the bootadm command to manually update the boot archives. For more information, see Using the bootadm Command to Manage the Boot Archives.

The failsafe archive can be booted for recovery purposes, or to update the boot archive.

On the SPARC platform the failsafe archive is:

/platform/`uname -m`/failsafe

You would boot the failsafe archive by using the following syntax:

ok boot -F failsafe

Failsafe booting is also supported on systems that are booted from Oracle Solaris ZFS. When booting from a ZFS-rooted BE, each BE has its own failsafe archive. The failsafe archive is located where the root file system is located, as is the case with a UFS-rooted BE. The default failsafe archive is the archive that is in the default bootable file system. The default bootable file system (dataset) is indicated by the value of the pool's bootfs property.

For information about booting an x86 based failsafe archive, see Booting an x86 Based System in Failsafe Mode.

For information about clearing automatic boot archive failures, see x86: How to Clear Automatic Boot Archive Update Failures by Using the auto-reboot-safe Property.

How to Boot a SPARC Based System in Failsafe Mode

Use this procedure to boot a SPARC based system in failsafe mode for the purpose of updating the boot archive. If the system does not boot after the boot archive is updated, you might need to boot the system in single-user mode. For more information, see SPARC: How to Boot a System to Run Level S (Single-User Level).

1. Become superuser or assume an equivalent role.

   Roles contain authorizations and privileged commands. For more information about roles, see Configuring RBAC (Task Map) in System Administration Guide: Security Services.

2. Bring the system to the ok prompt:

   # init 0

3. Boot the failsafe archive.
   • To boot the default failsafe archive, type:

     ok boot -F failsafe

   • To boot the failsafe archive of a specific ZFS dataset:

     ok boot -F failsafe -Z dataset

     For example:

     ok  boot -F failsafe -Z rpool/ROOT/zfsBE2

     ---

     Note - To determine the name of the dataset to boot, first use the boot -L command to display a list of the available BEs on the system. For more information, see SPARC: How to List Available Bootable Datasets Within a ZFS Root Pool.

     ---

   If an inconsistent boot archive is detected a message is displayed.

4. To update the boot archive, type y, then press Return.

   An out of sync boot archive was detected on rpool.
   The boot archive is a cache of files used during boot
   and should be kept in sync to ensure proper system operation.
   
   Do you wish to automatically update this boot archive? [y,n,?] y

   If the archive was updated successfully, a message is displayed:

   The boot archive on rpool was updated successfully.

Example 12-7 SPARC: Booting a System in Failsafe Mode

This example shows how to boot a SPARC based system in failsafe mode. If no device is specified, the failsafe archive for the default boot device is booted.

ok boot -F failsafe
Resetting ...
screen not found.
Can't open input device. Keyboard not present.  Using ttya for input and output.

Sun Enterprise 220R (2 X UltraSPARC-II 450MHz), No Keyboard
OpenBoot 3.23, 1024 MB memory installed, Serial #13116682.
Ethernet address 8:0:20:c8:25:a, Host ID: 80c8250a.

Rebooting with command: boot -F failsafe
Boot device: /pci@1f,4000/scsi@3/disk@1,0:a  File and args: -F failsafe
SunOS Release 5.10t
Copyright 1983-2007 Sun Microsystems, Inc.  All rights reserved.
Use is subject to license terms.
Configuring /dev Searching for installed OS instances...

An out of sync boot archive was detected on /dev/dsk/c0t1d0s0.
The boot archive is a cache of files used during boot and
should be kept in syncto ensure proper system operation.

Do you wish to automatically update this boot archive? [y,n,?] y 
Updating boot archive on /dev/dsk/c0t1d0s0.
The boot archive on /dev/dsk/c0t1d0s0 was updated successfully.

Solaris 5.10 was found on /dev/dsk/c0t1d0s0.
Do you wish to have it mounted read-write on /a? [y,n,?] n
Starting shell.
#

Example 12-8 SPARC: Booting a Specified ZFS Dataset in Failsafe Mode

This example shows how to boot the a ZFS dataset in failsafe mode. Note that the boot -L command is first used to display a list of available boot environments. This command must be run at the ok prompt.

ok boot -L
Rebooting with command: boot -L                                       
Boot device: /pci@1f,4000/scsi@3/disk@1,0  File and args: -L
1 zfsBE2
Select environment to boot: [ 1 - 1 ]: 1

To boot the selected entry, invoke:
boot [<root-device>] -Z rpool/ROOT/zfsBE2

Program terminated
{0} ok 





Resetting ... 

screen not found.
Can't open input device.
Keyboard not present.  Using ttya for input and output.

Sun Enterprise 220R (2 X UltraSPARC-II 450MHz), No Keyboard
OpenBoot 3.23, 1024 MB memory installed, Serial #13116682.
Ethernet address 8:0:20:c8:25:a, Host ID: 80c8250a.



                                                                      
{0} ok  boot -F failsafe -Z rpool/ROOT/zfsBE2
Boot device: /pci@1f,4000/scsi@3/disk@1,0  File and args: -F failsafe -Z 
rpool/ROOT/zfsBE2
SunOS Release 5.10
Copyright 1983-2008 Sun Microsystems, Inc.  All rights reserved.
Use is subject to license terms.
Configuring /dev
Searching for installed OS instances...

ROOT/zfsBE2 was found on rpool.
Do you wish to have it mounted read-write on /a? [y,n,?] y
mounting rpool on /a

Starting shell.
# 
# 
# 
# zpool list
NAME    SIZE   USED  AVAIL    CAP  HEALTH  ALTROOT
rpool  16.8G  6.26G  10.5G    37%  ONLINE  /a
# 
# zpool status
  pool: rpool
 state: ONLINE
 scrub: none requested
config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c0t1d0s0  ONLINE       0     0     0

errors: No known data errors
# 
# df -h
Filesystem             size   used  avail capacity  Mounted on
/ramdisk-root:a        163M   153M     0K   100%    /
/devices                 0K     0K     0K     0%    /devices
/dev                     0K     0K     0K     0%    /dev
ctfs                     0K     0K     0K     0%    /system/contract
proc                     0K     0K     0K     0%    /proc
mnttab                   0K     0K     0K     0%    /etc/mnttab
swap                   601M   344K   601M     1%    /etc/svc/volatile
objfs                    0K     0K     0K     0%    /system/object
sharefs                  0K     0K     0K     0%    /etc/dfs/sharetab
swap                   602M   1.4M   601M     1%    /tmp
/tmp/root/etc          602M   1.4M   601M     1%    /.tmp_proto/root/etc
fd                       0K     0K     0K     0%    /dev/fd
rpool/ROOT/zfsBE2       16G   5.7G   9.8G    37%    /a
rpool/export            16G    20K   9.8G     1%    /a/export
rpool/export/home       16G    18K   9.8G     1%    /a/export/home
rpool                   16G    63K   9.8G     1%    /a/rpool