alt_root_vg command

Purpose

Creates a copy of (clones) the currently running system to an alternative disk.

Syntax

alt_root_vg [-g] [-z] [-bundle ... -location ... ] -target ...

Description

The alt_root_vg command allows users to copy the current root volume group to an alternate disk and to update the operating system to the next fix pack level, without taking the machine down for an extended period of time and mitigating outage risk. This can be done by creating a copy of the current rootvg on an alternate disk and simultaneously applying fix pack updates. If needed, the bootlist command can be run after the new disk has been booted, and the bootlist can be changed to boot back to the older level of the operating system.

Note: The target_disk cannot be a physical volume that is assigned to a shared memory pool (to be used as a paging space device by a shared memory partition). The administrator must avoid to use an existing or creating a virtual target devices (VTDs), volume groups, logical volumes, special device files, or file systems with names that have the alt prefix. For example, a volume group with the name altinst_rootvg. When you run the alt_root_vg command to copy the current root volume group to an alternative disk, the operation might remove, alter, or damage the VTDs, volume groups, logical volumes, special device files, or file systems that exist with names that have the alt prefix.

Cloning the running rootvg, allows the user to create a backup copy of the root volume group. This copy can be used as a back up in case the rootvg failed, or it can be modified by installing additional updates. One scenario might be to clone a 1.3.0.0 system, and then install updates to bring the cloned rootvg to 1.3.0.0-FP8.0. This would update the system while it was still running. Rebooting from the new rootvg would bring the level of the running system to 1.3.0.0-FP8.0. If there was a problem with this level, changing the bootlist back to the 1.3.0.0 disk and rebooting would bring the system back to 1.3.0.0. Other scenarios would include cloning the rootvg and applying individual fixes, rebooting the system and testing those fixes, and rebooting back to the original rootvg if there was a problem.

At the end of the installation, a volume group, altinst_rootvg, is left on the target disks in the varied off state as a placeholder. If varied on, it indicates that it owns no logical volumes; however, the volume group does contain logical volumes, but they have been removed from the Object Data Manager (ODM) because their names now conflict with the names of the logical volumes on the running system. Do not vary on the altinst_rootvg volume group; instead, leave the definition there as a placeholder.

After rebooting from the new alternate disk, the former rootvg volume group is displayed in a lspv listing as old_rootvg, and it includes all disks in the original rootvg. This former rootvg volume group is set to not vary-on at reboot.

If a return to the original rootvg is necessary, the bootlist command is used to reboot from the original rootvg.

Flags

Flag name	Description
-target	Specifies a space-delimited list of the name or names of the target disks where the alternate rootvg clone is created. These disks must not contain any volume group definitions. The lspv command shows these disks because they belong to the None volume group.
-bundle	Specifies the path name of an optional file that contains a list of packages or filesets that are installed after a rootvg clone is created. You must also specify the -location flag when you specify the bundle option. To update all the currently installed software to the latest level that is available on the installation media, specify the update_all option instead of the bundle_name option. The update_all option updates only the currently installed software and does not install new software or bundles.
-location	Specifies the location of the installp images or updates to apply after a clone of rootvg is created. The location can be a directory and full-path name or device name, such as /dev/rmt0.
-g	Skips checks to ensure the disk can boot.
-z	Specifies that no types of non-rootvg volume groups are to be imported.

Exit Status

See Exit status for Virtual I/O Server commands.

Examples

To create a boot list of logical devices to be used in the next normal boot, enter the following commands:

alt_root_vg -target hdisk2 -bundle my_bundle -location /tmp/update
alt_root_vg -target hdisk2 -bundle my_bundle -location /home/padmin

Related Information

The bootlist command.

Last updated: Wed, November 18, 2020