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NIM Server Simplifies Installing and Upgrading AIX

NIM Simplifies AIX

Installing and upgrading your AIX* OS can be done in numerous ways.

For starters, you can install it from base media that’s downloadable from IBM. It’s simply a matter of populating your virtual media library with the appropriate images and using virtual DVDs and virtual SCSI adapters. The downside to using base media is that it requires customization once the OS is installed. This wasn’t a problem back when we were running one OS on each physical machine, but when you’re looking at loading many images onto a single physical frame, scalability becomes an issue.

Logically moving the install media devices and adding custom scripts, user IDs, cron jobs and site-specific information to your LPARs can also be time-consuming if done manually. Over time, many sites have just taken to upgrading and migrating existing systems rather than reinstalling them.

Alternatively, using the current versions of the VIO server and AIX, you can install your OS from images that you copy to USB flash drives. Flash drives are fast and by installing VIOS from USB, they solve the chicken and egg dilemma of how to install an OS when you’re installing the first machine in the data center. However, many of the same pitfalls apply with flash drives.

While many organizations install AIX using IBM PowerVC* virtualization and cloud manager to capture and deploy OS images, this method isn’t for everyone. Some encounter difficulties when coordinating among siloed teams to get PowerVC virtualization and cloud manager operational. (For one example, consider SAN teams that would have to allow access to their switches. This sort of bureaucracy can be overwhelming if you’re tasked with getting a green-field environment up and running quickly.)

The Advantages of NIM

So yes, when it comes to installing AIX, you have options. But for me, there’s only one real choice: the Network Installation Manager (NIM). NIM runs on an AIX LPAR, making it simple to deploy, even for those who haven’t previously used it. I also appreciate the control NIM gives me. I can choose where in the environment to run NIM, and I can have multiple NIM servers in multiple locations.

In addition, NIM is great for upgrades and migrations. If you need to migrate an older system to new hardware, you can take a backup image (in AIX it’s known as a mksysb) and bypass hardware limitations that might exist with older AIX versions. Yes, you can do the same thing from base media, but again, to make the solution scale, it’s best to use the network. Assuming your NIM server has the appropriate resources, it’s no trouble kicking off multiple installs or updates simultaneously.

NIM runs on an AIX LPAR, making it simple to deploy, even for those who haven’t previously used it. I also appreciate the control NIM gives me. I can choose where in the environment to run NIM, and I can have multiple NIM servers in multiple locations.
–Rob McNelly, Power Systems architect for Meridian IT

I also use NIM for alt_disk_ migrations and alt_disk_upgrades. By cloning your OS’s root volume group (rootvg) to a spare disk, you can perform operations on that volume group copy. Rather than take time during a change window, you can perform the upgrade beforehand, without affecting your running workloads. When you want to take backups, take them directly to your NIM server. If you already have a mksysb image, you can copy it to your NIM server. Then, after creating a spot, you can use that backup image to either restore or clone your LPAR.

Finally, as it’s sometimes difficult to get ports opened in enterprises, there’s also an option to use HTTP with your NIM server.

As I previously stated, NIM is easy to use, but it has one important requirement: Your NIM master must be at the highest level of AIX in your environment. You can’t use an older AIX version to install or restore a newer AIX version.

NIM Is Tried and True

As you evaluate different methodologies for performing installations, patching and ongoing maintenance in your environment, it’s easy to overlook tools we’ve been using confidently for years. Although newer options like PowerVC and BigFix* software (which uses NIM under the covers) will continue to gain wider adoption going forward, in my opinion, nothing beats the tried and true NIM server.

Rob McNelly is a Senior AIX Solutions Architect for Meridian IT Inc. and a technical editor for IBM Systems Magazine. He is a former administrator for IBM. Rob can be reached at



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