Administration Guide

Using alternate root volume groups

PSSP 3.1 provides support for alternate root volume groups. This means that you can install several different versions of AIX on different disks that are connected to the same node. That node can then easily be switched from operating with one version to another by rebooting from the disk that has the root volume group of your choice.

Alternate root volume groups can be useful, such as for switching between versions of AIX that have different levels of security, or for quickly backing out from testing new software levels to running production work.

To create alternate root volume groups use the spmkvgobj command and to remove them use the sprmvgobj command. Use the spbootins command to specify which root volume group is to be used in the next install. Use the spbootlist command to set the node's bootlist before rebooting. See the book PSSP: Command and Technical Reference for details of how to use these commands.

Examples of some typical tasks follow.

Installing a new root volume group

To create a new volume group called newvg on hdisk1 with an lpp source name of aix432 on nodes 3 and 5, do the following:

1. Create a new volume group:

   spmkvgobj -r newvg -h hdisk1 -v aix432 -l 3,5
   

2. Change the selected volume group to newvg, set the bootp response to install, and run the setup_server command:

   spbootins -c newvg -r install -l 3,5
   

   Note:

   The spbootins command runs the setup_server command by default.

3. Network boot the nodes:

   nodecond 1 3 &
   nodecond 1 5
   

The nodes are installed with the information specified in the newvg volume group and will reboot from the specified disks.

Note:

The bootp response is automatically set to disk.

Rebooting a node from an alternate root volume group

To switch from operating with the newvg volume group on hdisk1 to operating with the oldvg volume group on hdisk0, do the following:

1. Change the current volume group as recorded in the SDR:

   spbootins -c oldvg -l 3,5
   

2. Set the bootlists:

   spbootlist -l 3,5
   

3. Reboot the nodes:

   cshutdown -r -N 3 5
   

Removing an alternate root volume group

A volume group that is not the current root volume group can be removed. To remove the newvg volume group now that it is not the current volume group, issue the following command:

sprmvgobj -r newvg -l 3,5