Solaris 9 Installation Guide

Solaris Live Upgrade Introduction

Solaris Live Upgrade provides a method of upgrading that substantially reduces the usual service outage that is associated with an operating system upgrade. You can duplicate your current running boot environment, then while the original boot environment continues to run, you can upgrade the duplicate. Or, rather than upgrading, you can install a Solaris Flash archive on a boot environment. The original system configuration remains fully functional and unaffected by the upgrade or installation of a Solaris Flash archive. The duplicate boot environment is then activated to become the active boot environment when the system is rebooted. If a failure occurs, you have a safety net. You can quickly revert to the original boot environment with a simple reboot, thereby eliminating the downtime associated with the normal test and evaluation process.

Solaris Live Upgrade enables you to create copies of a boot environment without affecting the currently running system to do the following:

Some understanding of basic system administration is necessary before using Solaris Live Upgrade. For background information on system administration tasks such as managing file systems, mounting, booting, and managing swap, see the System Administration Guide: Basic Administration.

Solaris Live Upgrade Process

The following is an overview of the tasks necessary to create an inactive boot environment, upgrade it, and switch it to become the active boot environment.

Creating a Boot Environment Overview

Creating a boot environment provides a method of copying critical file systems from an active boot environment to a new boot environment. The disk is reorganized if necessary, file systems are customized, and the critical file systems are copied to the new boot environment.

File Systems Overview

Solaris Live Upgrade distinguishes between two file system types: critical file systems and shareable file systems. Critical file systems are required by the Solaris operating environment and are separate mount points in the vfstab of the active and inactive boot environments. Examples are root (/), /usr, /var, or /opt. These file systems are always copied from the source to the inactive boot environment. Critical file systems are sometimes referred to as non-shareable. Shareable file systems are user-defined files such as /export that contain the same mount point in the vfstab in both the active and inactive boot environments. Therefore, updating shared files in the active boot environment also updates data in the inactive boot environment. When you create a new boot environment, shareable file systems are shared by default. But you can specify a destination slice and then the file systems are copied. For more detailed information on shareable file systems, see Guidelines for Selecting Slices for Shareable File Systems.

Swap is a special circumstance of a shareable file system. Like a shareable file system, all swap slices are shared by default. But, if you specify a destination directory for swap, the swap slice is copied. You achieve this goal by using the character user interface or at the command line by using lucreate(1M) with the -m option. A limitation to splitting and merging swap slices is that the swap slice cannot be in use by any boot environment except the current boot environment or if the -s option is used, the source boot environment. The boot environment creation fails if the swap slice is being used by any other boot environment, whether the slice contains a swap, UFS, or any other file system. A swap slice is not required. For procedures on reconfiguring swap, see “To Create a Boot Environment (Character Interface)” Step 9, or To Create a Boot Environment and Reconfigure Swap (Command-Line Interface).

Note –

When you create file systems for a boot environment, the rules are identical to the rules for creating file systems for the Solaris operating environment. Solaris Live Upgrade cannot prevent you from making invalid configurations on critical file systems. For example, you could enter an lucreate command that would create separate file systems for root (/) and /kernel—an invalid division of root (/).

Copying File Systems

Creating a new boot environment entails copying critical file systems to another slice. The disk might need to be prepared before you create the new boot environment. Check the disk to make sure it is formatted properly:

The process of creating a new boot environment begins by identifying an unused slice where the critical file systems can be copied. If a slice is not available or a slice does not meet the minimum requirements, you need to format a new slice. For the procedure on formatting a slice from menus, see “To Create a Boot Environment (Character Interface)” Step 6.

After the slice is defined, you can reconfigure the file systems on the new boot environment before the file systems are copied into the directories. You reconfigure file systems by splitting and merging them, which provides a simple way of editing the vfstab to connect and disconnect file system directories. You can merge file systems into their parent directories by specifying the same mount point, or you can split file systems from their parent directories by specifying different mount points.

For procedures on splitting and merging file systems, see the following procedures:

After file systems are configured on the inactive boot environment, you begin the automatic copy. Critical file systems are copied to the designated directories. Shareable file systems are not copied, but are shared. The exception is that you can designate some file systems to be copied. When the file systems are copied from the active to the inactive boot environment, the files are directed to the newly defined directories. The active boot environment is not changed in any way. For procedures on creating a new boot environment, see Creating a New Boot Environment.

The following figures illustrate various ways of creating new boot environments.

Upgrading a Boot Environment Overview

After you have created a boot environment, it remains unchanged until you are ready to upgrade it. You can perform an upgrade on the boot environment at any time. The upgrade does not affect any files in the active boot environment. When you are ready, you then activate to the new release.

Figure 30–4 shows an upgrade to an inactive boot environment. For procedures on upgrading a boot environment, see Chapter 33, Upgrading With Solaris Live Upgrade (Tasks).

Figure 30–4 Upgrading an Inactive Boot Environment

The context describes the illustration.

Rather than an upgrade, you can install a Solaris Flash archive on a boot environment. The Solaris Flash installation feature enables you to create a single reference installation of the Solaris operating environment on a system that is called the master system. Then, you can replicate that installation on a number of systems that are called clone systems. In this situation, the inactive boot environment is a clone. For more information about the Solaris Flash installation feature, see Chapter 16, Solaris Flash Installation Feature (Topics).

When you install the Solaris Flash archive on a system, the archive replaces all the files on the existing boot environment as an initial installation would. Figure 30–5 shows an installation of a Solaris Flash archive on an inactive boot environment. For procedures on installing a Solaris Flash archive, see Installing Solaris Flash Archives on a Boot Environment.

Figure 30–5 Installing a Solaris Flash Archive

The context describes the illustration.

Activating a Boot Environment Overview

When you are ready to switch and make the new boot environment active, you quickly activate the new boot environment and reboot. When you activate the new boot environment, it is made bootable. Files are synchronized between boot environments the first time that you boot a newly created boot environment. "Synchronize" here means that certain system files and directories are copied from the last-active boot environment to the boot environment being booted. When you reboot the system, the configuration that you installed on the new boot environment is active. The original boot environment then becomes an inactive boot environment. Figure 30–6 shows a switch after a reboot from an inactive to an active boot environment. For procedures on activating a boot environment, see Activating a Boot Environment.

Figure 30–6 Activating an Inactive Boot Environment

The context describes the illustration.

Fall Back to the Original Boot Environment Overview

If a failure occurs, you can quickly fall back to the original boot environment with an activation and reboot. You need to fall back if the new boot environment cannot be booted, or if the new environment boots but does not work completely, or you are not satisfied with the results.

The use of fallback takes only the time to reboot the system, which is much quicker than backing up and restoring the original. The new boot environment that failed to boot is preserved. The failure can then be analyzed. You can only fall back to the boot environment that was used by luactivate to activate the new boot environment.

You fall back to the previous boot environment the following ways:

For procedures to fall back, see Failure Recovery: Falling Back to the Original Boot Environment (Command-Line Interface).

Figure 30–7 shows the switch that is made when you reboot to fallback.

Figure 30–7 Fallback to the Original Boot Environment

The context describes the illustration.

Maintaining a Boot Environment Overview

You can also do various maintenance activities such as renaming or deleting a boot environment. For maintenance procedures, see Chapter 34, Maintaining Solaris Live Upgrade Boot Environments (Tasks).