Solaris 11 Alternate Boot Environments

Solaris 11 Alternate Boot Environments

Introduction to Managing Boot Environments :

• A boot environment is a bootable Oracle Solaris environment consisting of a root dataset and, optionally, other datasets mounted underneath it. Exactly one boot environment can be active at a time.
• A dataset is a generic name for ZFS entities such as clones, file systems, or snapshots. In the context of boot environment administration, the dataset more specifically refers to the file system specifications for a particular boot environment or snapshot.
• A snapshot is a read-only image of a dataset or boot environment at a given point in time. A snapshot is not bootable.
• A clone of a boot environment is created by copying another boot environment. A clone is bootable.
• Shared datasets are user-defined directories, such as /export, that contain the same mount point in both the active and inactive boot environments. Shared datasets are located outside the root dataset area of each boot environment.

About the beadm Utility : 

• The beadm utility enables you to perform the following tasks:
• Create a new boot environment based on the active boot environment
• Create a new boot environment based on an inactive boot environment
• Create a snapshot of an existing boot environment
• Create a new boot environment based on an existing snapshot
• Create a new boot environment, and copy it to a different zpool
• Create a new boot environment and add a custom title to the x86 GRUB menu or the SPARC boot menu
• Activate an existing, inactive boot environment
• Mount a boot environment
• Unmount a boot environment
• Destroy a boot environment
• Destroy a snapshot of a boot environment
• Rename an existing, inactive boot environment
• Display information about your boot environment snapshots and datasets
• The beadm utility has the following features:
• Aggregates all datasets in a boot environment and performs actions on the entire boot environment at once. You no longer need to perform ZFS commands to modify each dataset individually.
• Manages the dataset structures within boot environments. For example, when the beadm utility clones a boot environment that has shared datasets, the utility automatically recognizes and manages those shared datasets for the new boot environment.
• Enables you to perform administrative tasks on your boot environments in a global zone or in a non-global zone.
• Automatically manages and updates the GRUB menu for x86 systems or the boot menu for SPARC systems. For example, when you use the beadm utility to create a new boot environment, that environment is automatically added to the GRUB menu or boot menu.

How to Create a Boot Environment
              beadm create BeName
              beadm create solaris-1

Activate the boot environment.
              beadm activate BeName

Listing Existing Boot Environments and Snapshots
              beadm list
                            -a – Lists all available information about the boot environment. This information includes subordinate datasets and snapshots.
                            -d – Lists information about all subordinate datasets that belong to the boot environment.
                            -s – Lists information about the snapshots of the boot environment.
                            -H – Prevents listing header information. Each field in the output is separated by a semicolon.

Viewing Boot Environment Specifications
              beadm list -a solaris-1

The values for the Active column are as follows:
R – Active on reboot.
N – Active now.
NR – Active now and active on reboot.
“-” – Inactive.
“!” – Unbootable boot environments in a non-global zone are represented by an exclamation point.


Viewing Snapshot Specifications
              beadm list -s solaris-1

Changing the Default Boot Environment
              beadm activate BeName
              beadm activate solaris-1

Destroying a Boot Environment
              beadm destroy solaris-1

If a Solaris server not booting after updating the patches, Boot the server from alternated boot environment
SPARC: How to Boot From an Alternate Operating System or Boot Environment
Bring the system to the ok PROM prompt.
Display a list of available boot environments by using the boot command with the -L option.
              boot -L

To boot a specified entry, type the number of the entry and press Return:
Select environment to boot: [1 - 2]:
To boot the selected entry, invoke:
boot [<root-device>] -Z rpool/ROOT/boot-environment

              boot -Z rpool/ROOT/boot-environment
              boot -Z rpool/ROOT/zfs2BE





~Judi~