Edit: Some links no longer work.
Originally posted September 3, 2013 on AIXchange
Recently I received this query:
“I wonder if you have a basic tutorial describing the steps needed to restore an AIX server. I am thinking of a scenario similar to the following:
“You have an AIX server with some applications and/or databases running on it. A disaster occurs, and you need to restore the server. I have access to a backup taken by a TSM server. So, what I think that could be done is the following:
1. Insert the AIX DVD in the server.
2. Using the HMC console Boot in SMS mode (press F1 or ESC 1 several times when the IBM banner is show on screen).
3. Choose the DVD as boot device.
4. Boot the server from DVD.
5. Select the disk to do the OS install.
6. Select the packages to be installed (do a basic install).
7. Once the OS is installed, the server will reboot.
8. Configure the root password, the network and several basic things.
9. Access the server from the network to Install TSM client and configure it.
10. Restore the backup from TSM.
“What do you think?”
What I think is that while this might be a reasonable way to restore a system that runs another OS, you needn’t go to all this trouble with AIX. I recommend using the mksysb command, which “creates a backup of the operating system (that is, the root volume group). You can use this backup to reinstall a system to its original state if it is corrupted. If you create the backup on tape or UDFS capable media, the backup is bootable and includes the installation programs needed to install from the backup.”
Even though many of you are familiar with mksysb, I wanted to post this question to make a point: Lots of people are new to AIX these days. For the most part, they’re been working in UNIX environments, and then through employer acquisition/job change or what have you, they’re suddenly charged with maintaining AIX systems. They might not realize that NIM and mksysb images are even options. Fortunately, they can seek advice and access others resources to learn more about the platform.
Now, back to the question. I would first make sure I had a good, recent mksysb. This allows you to skip step 1. In step 2, when I was in SMS mode, I’d make sure the networking information allowed for booting from the NIM server. Boot from the NIM; don’t use AIX media. Once the restore was completed, I could skip steps 6-9 and proceed to step 10.
The other advantage with NIM is that it gives me a clone of the system. Obviously you don’t want to have to reload the system, and try and recall all the packages and settings that you had installed, in the aftermath of a disaster. Make sure you are taking your backups. You never know when you might really need it.
For additional information on this topic, there’s this good article by Jaqui Lynch. I’ve also covered NIM on this blog (here and here). Can you think of any circumstances that would require you to completely rebuild an AIX machine from scratch in a disaster situation?