Edit: Anyone still running 5.3? Some links no longer work.
Originally posted September 18, 2012 on AIXchange
I was recently asked about potential issues running AIX 5.3 with the latest fixes on POWER7 hardware with dedicated adapters. Somehow this person had gotten the idea that AIX 5.3 could only handle the underlying hardware and adapters by running in a virtualized environment using VIO servers.
Perhaps this person thought that since AIX 5.3 needs to run in POWER6 mode, the newer physical adapters wouldn’t be supported with an old version of the operating system. These days I typically run everything in a virtualized environment using VIO servers, and just off of the top of my head I can’t recall the last time I needed to dedicate an adapter to an AIX 5.3 LPAR on POWER7 hardware.
However, rather than shoot my mouth off, I quickly checked some Redbooks and asked some trusted resources. They confirmed what I figured: AIX 5.3 can most definitely handle all of the latest adapters you can throw at it. Absolutely.
This highlights one of the many strengths of using IBM solutions. From the hardware to the firmware to the hypervisor to the operating systems, one vendor owns the stack. Thus, IBM can ensure that any new hardware and adapters will continue to run with its legacy operating systems.
Speaking of AIX 5.3, remember that even though it’s no longer in support, AIX 5.3 is still eligible for extended support contracts. Another way to get support for your legacy OS is through AIX 5.3 versioned WPARs (see here and here). With this option you can run in POWER7 mode with four threads. IBM also provides bug fixes and how-to support if you choose to run 5.3 WPARs. Obviously running in POWER7 mode should give you a nice a performance boost over using two threads in POWER6 mode.
That IBM makes these options available is all the more impressive when you realize that AIX 5.3 debuted in 2004. You can see how someone would assume that current hardware couldn’t possibly support an eight-year-old operating system.
An item from the above link:
“As new hardware becomes available over the next two years, we will provide new hardware toleration when possible. This will not include new hardware that requires architectural changes.”
Also:
“Some people have asked me about when they should use the AIX 5.3 service extension versus using the AIX 5.3 Workload Partitions product. The answer is pretty easy – if you intend to migrate to a later release of AIX, then use the service extension to bridge you to that point. If however, you believe that you will need to run AIX 5.3 indefinitely for a particular application, then the AIX 5.3 WPARs is the better choice.”
So where are you on this? Have you already migrated all of your systems? Do you have extended support? Do you use the AIX 5.2 or 5.3 versioned WPAR offerings? Do you even know about them?