4.7 Creating Installation Images on a Hard Disk

4.8 Alternate Disk Installation

Alternate disk installation, available in AIX Version 4.3, allows installing the system while it is still up and running, which allows install or upgrade downtime to be decreased considerably. It also allows large facilities to manage an upgrade because systems can be installed over a longer period of time while the systems are still running at the existing version. The switch over to the new version can then happen with a simple reboot.

4.8.1 Filesets Required

Alternate disk installation requires the following filesets to be installed before you are able to use the functions. The filesets are:

• bos.alt_disk_install.boot_images filesets must be installed for alternate disk mksysb installs if Network Install Management (NIM) is not being used.

• bos.alt_disk_install.rte fileset must be installed for rootvg cloning.

Once you have installed these filesets, the alternate disk installation functions are available to you in the Software Installation and Maintenance menu. Use the SMIT fast path:

smitty alt_install.

A screen similar to Figure 33 is shown.



Figure 33: Alternate Disk Installation

Alternate disk installation can be used in one of two ways:

• Cloning the current running rootvg to an alternate disk.

• Installing a mksysb image on another disk.

4.8.2 Alternate Disk rootvg Cloning

Cloning the rootvg to an alternate disk can have many advantages.

• Having an online backup available in case of disaster. Keeping an on-line backup requires that an extra disk or disks to be available on the system.

• Applying new maintenance levels or updates. A copy of the rootvg is made to an alternate disk, then updates are applied to that copy. Finally, the boot list is updated to boot from the new device. The system runs uninterrupted during this time. When it is rebooted, the system will boot from the newly updated rootvg for testing. If updates cause problems, the old rootvg can be retrieved by resetting the bootlist and rebooting.

In order to clone your rootvg to a new disk, do the following procedure:

Use the SMIT fast path:

1. smitty alt_clone

   A screen similar to Figure 34 is shown.
   
   
   
   Figure 34: smitty alt_clone
   
   

2. In the Target Disk(s) to install field, enter the name of the disk you want to use for making the clone. The target disk should be a stand-alone disk not belonging to a volume group. In addition to this, SSA disks cannot be used as your target disks.

3. The Phases to execute field defaults to all. Accept the default for now.

4. In the Exclude list field, you can create a file that will contain the names of all the files and directories that you do not want to be copied to your cloned system.

5. Specify the name of any additional bundles or filesets and fixes that you want to install in the Bundle to install and Fix to Install fields. The use of these fields allows service to be installed as part of the clone process.

6. Specify the name of the input device in case you have selected to install any additional software in the Directory or Device with images field.

7. If you want your system to start from your alternate rootvg on the next system start-up, set the Set the bootlist to boot from this disk on next boot to YES

8. Press Enter.

The following sequence of output is shown in SMIT while the system is cloning to the new disk:

Calling mkszfile to create new /image.data file.
Checking disk sizes
Creating cloned rootvg volume group and associated logical volumes
Creating Logical volume alt_hd5
Creating Logical volume alt_hd6
Creating Logical volume alt_hd8
Creating Logical volume alt_hd4
Creating Logical volume alt_hd2
Creating Logical volume alt_hd9var
Creating Logical volume alt_hd3
Creating Logical volume alt_hd1
Creating /alt_inst / file system
Creating /alt_inst/usr file system
Creating /alt_inst/var file system
Creating /alt_inst/tmp file system
Creating /alt_inst/home file system
Generating a list of files
for backup and restore into the alternate file system ...
Backing up the rootvg files and restoring them to the
alternate File Systems
Modifying ODM on cloned disk
Building boot image on cloned disk
Forced umount of /alt_inst/home
Forced umount of /alt_inst/tmp
Forced umount of /alt_inst/var
Forced umount of /alt_inst/usr
Forced umount of /alt_inst/
Changing logical volume names in Volume Group Descriptor Area
Fixing Logical Volume control blocks
Fixing File system super blocks
Bootlist is set to the bootdisk:hdisk1

By default, the bootlist will be set to the new cloned rootvg for the next reboot. This completes the cloning of the rootvg using the alt_disk_install command.

4.8.3 Alternate mksysb Install

An alternate mksysb install involves installing a mksysb image that has already been created from another system onto an alternate disk of the target system. The mksysb image (AIX Version 4.3 or later) would be created on a system that was either the same hardware configuration as the target system or would have all the device and kernel support installed for a different machine type or platform and/or different devices.

In order to create the alternate mksysb system, use the SMIT fast path:

1. smitty alt_mksysb

   A screen similar to Figure 35 is shown:
   
   
   
   Figure 35: smitty alt_mksysb
   
   

2. Enter the name of the disk on which you want to install the mksysb in the Target Disk(s) to install field.

3. Enter the name of the device or the image name from which you will be restoring the mksysb in the Device or image name field.

4. Press Enter.

Once the mksysb image is restored to the new disk, the system reboots from the new alternate rootvg. This completes your alternate mksysb installation.

4.9 Quiz