Dual-boot for Linux and AIX

Article title: dual-boot for Linux and AIX. Linux is a technology channel of the IT lab in China. Includes basic categories such as desktop applications, Linux system management, kernel research, embedded systems, and open source.
　　 Introduction
On the IBM eServer server that supports logical partitions, Linux and AIX should be run in different separate partitions. However, not all configurations support logical partitions, and sometimes all resources need to be available on the hardware. In these cases, the dual-boot Linux and AIX operating systems may be an effective way to provide each platform based on your needs. Unlike Linux for x86 servers, there is no public boot loader for dual-boot operating systems. Fortunately, OpenFirmware allows multiple boot devices to enable dual boot. This tool eliminates the need to manually switch the drive back and forth on the machine. Manual disk swap may cause users and operating systems to wonder which disk is the primary disk. This document assumes that you are familiar with Linux for POWER.™And AIX installation.
　　
　　 Configure dual boot from OpenFirmware
It is critical to use the OpenFirmware interface to select the boot device. Do not try to change the boot sequence by physically disconnecting the drive. Disconnecting the drive may lead to disorder in the drive sequence, then cause failure to boot the disk, and may cause data loss.
　　
The boot device configuration menu is located in the OpenFirmware menu system. After the machine is enabled, press 1 when "E1F1 to reach OpenFirmware" is displayed on the LCD status panel. In the main menu, perform the following steps:
　　
Select Option 7, that is, Select Boot Options.
Select option 2, that is, Select Boot Devices. This menu allows you to set the preferred sequence of Boot devices and will prepare the Multiboot menu (option 3 in the Select Boot Options menu) for future use.
Select Option 5 from the Select Device Type menu, that is, Hard Drive.
Select option 1 from the next menu, that is, SCSI. This menu allows you to set which disk to boot first by default. This menu also allows you to set the order of other disks in the Multiboot menu.
Select Task from the next menu, and then select M to return to the main menu.
You can repeat these steps if necessary to correctly set the boot sequence of the boot disk.
　　
To guide a specific disk in the future, you can return to the Select Boot Options menu and Select option 3, that is, the Multiboot menu. This menu allows you to set OpenFirmware so that it is always paused on the Multiboot menu during boot (so that you do not have to press the 1 key ). It also allows you to select disks that have been arranged using the preceding method.
　　
　　 Configure the boot device in the operating system
In Linux, you can use the nvsetenv tool (in/sbin) to configure the boot device to be used in the next boot. The tool must be used as root.
　　
With a simple script, you can set the candidate reboot command to allow the machine to reboot in Linux or AIX. The format used by/sbin/nvsetenv pilot device entries is the same as that provided in OpenFirmware. You can view the device name in OpenFirmware (see the previous section) and copy the information to the command line sent with/sbin/nvsetenv. For example:
　　
/Sbin/nvsetenv boot-device =/pci @ 400000000111/pci @/scsi @ 1/sd @: 1, \ ppc \ bootinfo.txt/pci @
400000000110/pci @ 2, 4/scsi @ 1/sd @ 8, 0
　　
Note: all code is a whole line, with only one space behind the txt.
　　
In AIX, you can use the bootlist command to perform the same operation. See the nvsetenv and bootlist manuals for auxiliary instructions on each tool.
　　
　　 Conclusion
Do not try to reorder boot devices by physically switching disks. You can use the console interface of OpenFirmware or a tool provided in Linux or AIX to change the sequence of boot devices. This protects your data and makes system maintenance easier.