Understanding AIX Versions
The oslevel command helps plan updates
If you're planning to update AIX, the method you use will depend on the version you're currently running. You can find that using the command “oslevel -s” (see Figure 1).
In this article I'll answer a few questions about AIX levels and the oslevel command:
- What's a TL? What's a Service Pack?
- When you run “oslevel -s”, what do all the numbers mean?
- Should you do a migration or a smitty update_all?
- What's the difference between applying and committing updates?
Armed with the answers to these, you can start planning your AIX updates. You can find excellent material on updating your AIX systems in the links below, but before you begin, you'll need to know your starting point.
Unraveling the Numbers
After the release of AIX base levels, such as AIX 5.3, 6.1 or 7.1, IBM regularly releases updates. These are packed together as Technology Levels (TLs) or Service Packs (SPs). The oslevel command reports the base and TL levels you have installed, and the “-s” flag includes service pack information.
If your system is running AIX 5.3 TL 6 or anything later, “oslevel -s” will look something like this: 6100-02-06-0943. Breaking that down, the first four numbers show the AIX base level. In this example, it's 6100, which means we're running AIX 6.1. Next is the Technology Level (TL), followed by the number of the Service Pack (SP). he last four digits show the release date of the Service Pack using the format YYWW (YY for the year, then WW for the week of the year). So, if your “oslevel -s” command reports 6100-02-06-0943, then you know you're on AIX 6.1, running TL 2, with SP 6. The “0943” tells you that Service Pack came out in week 43 of 2009. It’s time to update your system. See Figure 1 for some examples.
AIX TLs and SPs
A TL contains new functions and features. For example, when AIX 7.1 was released, some of its features–such as volume groups exclusively for solid state disks–were included in a new TL for AIX 6.1: TL 6. If you were already running AIX 6.1 but were on an older TL, you'd need to update to TL 6 to take advantage of those features.
A TL gives new features, while a SP contains fixes for problems that are critical and can't wait until the next TL. Service Packs are limited to minimal corrections that don't change the way things work or add any new functionality. (There are also interim fixes, which can't wait for the next SP to be released. Find out more about them in the AIX Service Strategy Details and Best Practices in the links below.)
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