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Should You Upgrade Your OS?

If you’re running on a very old version of AIX, it’s time to give serious thought to upgrading. Perhaps your OS is even out of support, but you’re still nervous about migrating to a new AIX release or updating to a new technology level (TL). After all, why tinker with a stable system?

If your system is old but stable, and you don’t have the plans or the time (or the budget) to upgrade the hardware or applications, then there might be a case for continuing with the OS you’re on. After all, application and OS upgrades require skills, testing and time, and you may be wondering whether upgrading is worth the effort.

Upgrade Benefits

In most cases, however, there are very good reasons for bringing your systems up to date. Some of the benefits are immediate. Others are less tangible but in the long run pay for themselves several times over, especially if you don’t have plans to decommission your applications anytime soon. If you have some systems with an OS that’s getting a bit long in the tooth, perhaps running on some old hardware, consider some of the advantages of bringing them up to date:

• New functionality. Vendors know they have to keep improving software in order to be able to offer a competitive advantage. That can only be good news for you as an end user—as long as you’re taking advantage of it. AIX 6 introduced several features that enhance virtualization, such as workload partitions (WPARs), live partition mobility (LPM), live application mobility and multiple shared processor pools. There are also security features such as the AIX Security Expert and Encrypted File System. AIX 7 went further, with features such as the ability to run AIX 5.2 WPARs, Cluster Aware AIX and enhanced support in the AIX Logical Volume Manager for Solid State Disk (SSD) drives, just to name a few. (Some of these features are not available on older hardware). Even if you don’t plan to use any of these features straight after an upgrade, by upgrading your OS you can give yourself the option of using them later on.
• Performance improvements, bug fixes, time savers. New releases and fixes of the OS include improvements in functionality and system performance. Tasks are often simplified; problems from earlier releases have been ironed out. These can be real time savers for you. Some of these benefits are hard to quantify, but if you do have a problem running old versions, you may first be asked to upgrade AIX and system firmware to new versions. Wouldn’t you rather do that with planning rather than an emergency upgrade of critical systems?
• Better hardware integration. With virtualization you can consolidate OS images from old, power-hungry hardware onto newer servers. This can dramatically reduce power and cooling costs, improve performance and allow you to consolidate AIX systems onto a single virtualized server.
• Application dependencies. One of the most common drivers for upgrading the OS is that it’s a prerequisite for an application upgrade. If an application upgrade was postponed because your OS was downlevel, upgrading the OS can make it easier to move to a newer version of your application.
• Hardware upgrade paths. An OS upgrade can also make it much easier to transition to new hardware in-house or via outsourcing.

Smooth Transition

Perhaps you can see the benefits of getting to a more recent level of your OS, but what about the procedure itself? Of course any upgrade has to be planned using proper change-management procedures. The good news is that upgrade procedures are getting simpler, faster and more robust. And in the unlikely event that you should need to roll back to the previous version, that can be as simple as a reboot.

On AIX you can use facilities such as alternate disk installation, mksysb migrations for a new release (e.g., from v5.3 to v7.1) or multibos for updates within the same release.

Low Risk

The benefits of doing an upgrade generally far outweigh the risks. For example, supposing you’re going to upgrade an AIX system to v7.1. You have IBM’s guarantee that AIX 7.1 is fully binary compatible with AIX 6 and AIX 5 releases. (See Resources.)

And if you’re still nervous about moving to AIX 7, you may be willing to go to a recent TL of AIX 6.1. Some of the features of AIX 7 are being backported to the later releases of AIX 6.1. For example, from AIX 6.1 TL 6 you can create volume groups just for solid-state drives (SSDs), and have Virtual SCSI (VSCSI) support for WPARs. There are, of course, features of AIX 7.1 that are not available in earlier releases, such as the ability to create AIX 5.2 WPARs. If you’re willing to forgo some of those AIX 7-specific features, you can still move to a more recent level of your OS, even if it’s not the latest available.

Inertia Exposure

If you still need to be convinced to move to a more recent OS level, think of the downside of staying put:

• You risk being out of support, for the OS and for applications. You could even face difficulties with support for storage or other hardware.
• There’s the expense of running on old hardware. Even if it continues to be reliable, it can be expensive to run (power, cooling, support costs).
• It is harder to find people with the skills and experience needed to maintain outdated versions.
• You may face a situation where a problem can only be fixed by a new OS release. That could involve an emergency upgrade of critical systems, without the chance to plan or test it first.

If you’re working on systems with old versions of the operating system, which perhaps have already gone out of support, take a look at bringing your systems up to date. Upgrades can be surprisingly easy, and the benefits are well worth the effort.

Resources

Upgrading to AIX 7, including the Binary Compatibility Guarantee

IBM AIX release and service-delivery strategy

AIX technology-level update strategies

AIX updates with multibos

Performing a mksysb migration

How-To’s for AIX installation tasks

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