Booting From an Alternate Operating System or Boot Environment

The following procedures are provided in this section:

x86: How to Boot From an Alternate Operating System or Boot Environment
SPARC: How to Boot From an Alternate Operating System or Boot Environment

A boot environment (BE) is a ZFS file system that is designated for booting. A boot environment is essentially a bootable instance of the Oracle Solaris OS image, plus any other software packages that are installed into that image. You can maintain multiple boot environments on a single system. Each boot environment can have different OS versions installed. When you install Oracle Solaris, a new boot environment is automatically created during the installation. For more information about the beadm utility, see the beadm(1M) man page. For more information about managing boot environments, including using the utility in a global or non-global zone, see Creating and Administering Oracle Solaris 11.1 Boot Environments.

x86 only: If the device that is identified by GRUB as the boot device contains a ZFS storage pool, the grub.cfg file that is used to create the GRUB menu can be found in the pool's top level dataset. This is the dataset that has the same name as the pool. There is always exactly one such dataset in a pool. This dataset is well-suited for pool-wide data, such as the GRUB configuration files and data. After the system is booted, this dataset is mounted at /pool-name in the root file system.

x86 only: There can be multiple bootable datasets (that is, root file systems) within a pool. The default root file system in a pool is identified by the pool' s bootfs property. If a specific bootfs is not specified with the zfs-bootfs command in a GRUB menu entry located in the grub.cfg file, the default bootfs root file system is used. Each GRUB menu entry can specify a different zfs-bootfs command to use, which enables you to choose any bootable Oracle Solaris instance within a pool. For more information, see the boot(1M) man page.

SPARC: How to Boot From an Alternate Operating System or Boot Environment

Assume the root role.
See How to Use Your Assigned Administrative Rights in Oracle Solaris 11.1 Administration: Security Services.
Bring the system to the ok PROM prompt.
```
# init 0
```
(Optional) Display a list of available boot environments by using the boot command with the -L option.
To boot a specified entry, type the number of the entry and press Return:
```
Select environment to boot: [1 - 2]:
```

To boot the system, follow the instructions that are displayed on the screen.

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

ok boot -Z rpool/ROOT/boot-environment

For example:

# boot -Z rpool/ROOT/zfs2BE

After the system has booted, verify the active boot environment.
```
# prtconf -vp | grep whoami
```
(Optional) To display the boot path for the active boot environment, type the following command:
```
# prtconf -vp | grep bootpath
```
(Optional) To determine whether the correct boot environment was booted, type the following command:
```
# df -lk
```

Example 4-10 SPARC: Booting From an Alternate Boot Environment

This example shows how to use the boot -Z command to boot from an alternate boot environment on a SPARC based system.

# init 0
root@t2k-brm-28:~# svc.startd: The system is coming down.  Please wait.
svc.startd: 126 system services are now being stopped.
Jul  3 22:11:33 t2k-brm-28 syslogd: going down on signal 15
svc.startd: Killing user processes.
umount: /home busy
Jul  3 22:11:50 The system is down.  Shutdown took 23 seconds.
syncing file systems... done
Program terminated
{1c} ok boot -L

SC Alert: Host System has Reset

Sun Fire T200, No Keyboard
Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
OpenBoot 4.30.4.d, 16256 MB memory available, Serial #74139288.
Ethernet address 0:14:4f:6b:46:98, Host ID: 846b4698.

Boot device: /pci@780/pci@0/pci@9/scsi@0/disk@0,0:a  File and args: -L
1 Oracle Solaris 11.1 SPARC
2 s11u1_backup
3 s11u1_backup2
Select environment to boot: [ 1 - 3 ]: 3

To boot the selected entry, invoke:
boot [<root-device>] -Z rpool/ROOT/s11u1_backup2

Program terminated
{0} ok boot -Z rpool/ROOT/s11u1_backup2

SC Alert: Host System has Reset

Sun Fire T200, No Keyboard
Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
OpenBoot 4.30.4.d, 16256 MB memory available, Serial #74139288.
Ethernet address 0:14:4f:6b:46:98, Host ID: 846b4698.



Boot device: /pci@780/pci@0/pci@9/scsi@0/disk@0,0:a  \
File and args: -Z rpool/ROOT/s11u1_backup2
SunOS Release 5.11 Version 11.1 64-bit
Copyright (c) 1983, 2012, Oracle and/or its affiliates. All rights reserved.
WARNING: consconfig: cannot find driver for
screen device /pci@780/pci@0/pci@8/pci@0/TSI,mko@0
Loading smf(5) service descriptions: Loading smf(5)
service descriptions: Hostname: system-28
.


system-28 console login: Jul  3 22:39:05 system-28

x86: How to Boot From an Alternate Operating System or Boot Environment

Assume the root role.
See How to Use Your Assigned Administrative Rights in Oracle Solaris 11.1 Administration: Security Services.
Perform a standard reboot the system.
```
# reboot -p
```
When the GRUB menu is displayed, navigate to the alternate boot environment or operating system that you want to boot.
To boot from the alternate operating system, press Control-X. If you have a system with UEFI firmware, and you are not using a serial console, pressing F10 also boots the alternate operating system.

Example 4-11 Booting From an Alternate Boot Environment by Using the reboot Command

You can boot an alternate boot entry by using the reboot command specifying the boot entry number, as shown in the following example:

# bootadm list-menu
the location of the boot loader configuration files is: /rpool/boot/grub
default 1
timeout 30
0 s11.1.backup
1 Oracle Solaris 11.1 B14
# reboot 1
Apr 23 16:27:34 system-04 reboot: initiated by userx on /dev/consoleTerminated
x4100m2-brm-04% syncing file systems... done
SunOS Release 5.11 Version 11.1 64-bit
Copyright (c) 1983, 2012, Oracle and/or its affiliates. All rights reserved.

Hostname: system-04

system-04 console login:

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