Section 13.7. System Cloning

13.7. System Cloning

Cloning a system is the action of restoring the complete image of one system onto a completely different system. The "restored" system is then a perfect image of the original one. This could be useful in the case of a fire or a similar catastrophe in which the hardware is completely lost. In such a case, you could use an off-site mksysb to recover the old system onto new hardware.

13.7.1. AIX 4.x Operating System

The 4.x versions of AIX require special attention because not all the drivers are installed with the BOS. In this case, you are left with two choices:

• Install all device drivers for all available architectures before taking the mksysb or backup of the system. That allows the tape to be booted from and restored onto any IBM RS/6000.

• If device drivers are not installed, you can simply boot the new machine from the CD-ROM containing the AIX 4.x operating system. After the boot, choose the Restore from tape backup option, insert the mksysb tape, and start the restore.

13.7.2. AIX 5.x Operating System

In AIX 5.x, all device drivers and supported kernels are installed with the BOS. This means that a system backup should be largely hardware-independent. However, there are issues when backing up older 32-bit systems. A system backup of a 32-bit AIX system running in 32-bit mode will still run in the same 32-bit mode if installed onto 64-bit hardware. A backup of a 64-bit system will not run on a 32-bit system because 32-bit hardware cannot run 64-bit software. To change system modes between 32 and 64 bits, see the IBM systems operation guide for the version of AIX you are running.

You should edit the bosinst.data file to set the RECOVER_DEVICES variable. This specifies whether or not to restore the ODM definitions that were in place at the time of the backup. Since this backup may be restored onto a machine with very different hardware, let AIX rebuild its own ODM definitions at boot.

If you make a bootable CD/DVD on a different platform, you must add the G flag to mkcd. This forces it to include the chrp, rs6k, and rspc boot images on the CD.

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