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The following installation methods are available on AIX:

New and Complete Overwrite
This method installs AIX 6.1 on a new machine or completely overwrites any BOS version that exists on your system.

This method replaces an earlier version of the BOS but retains the root volume group, the user-created logical volumes, and the /home file system. The system file systems /usr, /var, /tmp, /opt, and / (root) are overwritten. Product (application) files and configuration data stored in these file systems will be lost. Information stored in other non-system file systems will be preserved.

The migration installation method is used to upgrade from an existing version or release of AIX to a later version or release of AIX. A migration installation preserves most file systems, including the root volume group, logical volumes, and system configuration files. It overwrites the /tmp file system.




The standard dictates that the first part of the package name is the product name, the second is the package name, the third is the fileset name, and the fourth is the suffix that describes the contents of the fileset

LPPs (Licensed Program Product)
It is a complete software product collection including all packages and filesets required. For example, the Base Operating system (bos) itself is a LPP, which in turn is a complete collection of packages and filesets

A package contains a group of filesets. A package is also a single unit that can be installed. Several packages make up an LPP or product offering. For example, bos.net is a package.

A set of files that are installed together as a single unit. All licensed program products (including AIX itself) are packaged and delivered as one or more filesets. A fileset is the smallest individual unit that can be installed. It provides a specific function. For example, bos.net.tcp.nfs is a fileset in the bos.net package.


V.R.M.F    <-- Version.Release.Modification.Fix

TL (Technology Level, earlier ML: Maintainance Level)
A TL contains new hardware and software features and service updates,  all requisites are added to it, so that the whole TL is installed.

SP (Service Pack)

A Service Pack (SP) consists of service-only updates that are released between Technology Levels to be grouped together for easier identification.

CSP (Concluding Service Pack)
CSP is the last Service Pack for a Technology Level

APAR (Authorized Program Analysis Report)
IBM acknowledges that there is some sort of defect in a software program. An APAR is a number used to identify reported problems and it sums up the problem and instructs the software lab to fix it. A fix to an APAR can be made up of one or more fileset updates. (IXnnnnn or IYnnnnn number - and not long ago IZnnnnn) --> instfix

PTF (Program Temporary Fix)
A PTF is a Program Temporary Fix and provides a solution for a problem. (Unnnnnn number for AIX) I guess the U is for UNIX) --> instfix

INTERIM FIX (efix, ifix)
It's a temporary correction -->emgr

Most people use PTF and APAR interchangably. PTF's have the word temporary in them but really are not temporary, they are just a patch.
A temporary patch would be an efix (ifix) that you would get directly from IBM. Ifixes need to be uninstalled before a TL update (as these ifixes should be contained in the new TL level). The terminology is confusing but just think of both PTF's and APAR's as patches. There could be some sort of technical difference between the two but it doesn't really matter.

Starting in AIX 5.3 TL 10 and AIX 6.1 TL 3, the installp command will automatically remove an ifix from the system if you are installing the Technology Level, Service Pack, or PTF that provides the official fix for the problem.


 When to do updates:

"How often should you upgrade your systems and install service packs? What about the firmware and the HMC, how often are these updated? The short answer is: there’s no right or wrong way. Some clients need an environment that requires maximum uptime and availability. These clients typically wait until new TLs are available for several months, and at least three SPs have been released prior to deploying a new release.

Other folks prefer to be current so they can fully take advantage of all of the features and functionality a new TL brings, while at the same time ensuring that they have the latest security patches and OS patches. Regarding firmware, unless there’s a compelling reason, I prefer to wait until I’m more than one level down prior to upgrading. This way, I’m reasonably current but not too bleeding edge; I like to let others work out the hardware bugs."



Install terminology:

In order to support diskless or dataless client workstations, machine-specific portions of the package (the root part) must be separated from the machine-shareable portions of the package (the usr part).

root part
The root part of the software contains files that must be installed on the target system. It contains the part of the product
that cannot be shared among machines. Each client must have its own copy.

usr part
The object classes in this repository can be shared across the network by /usr clients, dataless and diskless workstations. Software installed in the /usr-part can be shared among several machines with compatible hardware architectures.

A prerequisite indicates that the specified fileset must be installed at the specified fileset level or at a higher level before the current fileset can install successfully.

A corequisite indicates that the specified fileset must be installed for the current fileset to function successfully. At the end of the installation process, the installp command issues warning messages for any corequisites that are not met. A corequisite can be used to indicate requisites between filesets within the same package. (filesets listed as coreq must be installed at the same time as the fileset what we want to install)

The (InstalledFilesetLevel) parameter is optional. For example, if the RequiredFilesetLevel is and no InstalledFilesetLevel parameter is supplied, the InstalledFilesetLevel is If the RequiredFilesetLevel is and no InstalledFilesetLevel parameter is supplied, the InstalledFilesetLevel is

An installed requisite indicates that the specified fileset should be installed automatically only if its corresponding fileset is already installed or is on the list of filesets to install. An installed requisite also is installed if the user explicitly requests that it be installed.

Group Requisite
A group requisite indicates that different requisite conditions can satisfy the requisite. A group requisite can contain prerequisites, corequisites, if-requisites, and nested group requisites. The Number preceding the { RequisiteExpressionList } identifies how many of the items in the RequisiteExpressionList are required. For example, >2 states that at least three items in the RequisiteExpressionList are required.


Example #1 (prereq, coreq, ifreq):

Fileset new.fileset.rte contains the following requisites:

*prereq database.rte
*coreq spreadsheet.rte
*ifreq wordprocessorA.rte (
*ifreq wordprocessorB.rte

The database.rte fileset must be installed at level or higher before the new.fileset.rte fileset can be installed. If database.rte and new.fileset.rte are installed in the same installation session, the installation program installs the database fileset before the new.fileset.rte fileset.

The spreadsheet.rte fileset must be installed at level or higher for the new.fileset.rte fileset to function properly. The spreadsheet.rte fileset does not need to be installed before the new.fileset.rte fileset is installed, provided both are installed in the same installation session. If an adequate level of the spreadsheet.rte fileset is not installed by the end of the installation session, a warning message will be issued stating that the corequisite is not met.

If the wordprocessorA.rte fileset is installed (or being installed with new.fileset.rte) at level, then the wordprocessorA.rte fileset update must be installed at level or higher.

If the wordprocessorB.rte fileset is installed (or being installed with new.fileset.rte) at level, then the wordprocessorB.rte fileset update must be installed at level or higher.


Example #2 (instreq):

Fileset Super.msg.fr_FR.Widget at level contains the following install requisite:

*instreq Super.Widget

The Super.msg.fr_FR.Widget fileset cannot be installed automatically when the Super.Widget fileset is not installed. The Super.msg.fr_FR.Widget fileset can be installed when the Super.Widget fileset is not installed if the fileset is listed explicitly on the list of filesets to be installed..


Example #3 (group reqisite):

At least one of the prerequisite filesets listed must be installed (both can be installed). If installed, the spreadsheet_1.rte fileset must be at level or higher or the spreadsheet_2.rte fileset must be at level or higher.

>0 {
*prereq spreadsheet_1.rte
*prereq spreadsheet_2.rte



A newer fileset supersedes any older version of that fileset.

For example, the fileset update farm.apps.hog delivers an update of /usr/sbin/sellhog. Fileset update farm.apps.hog delivers updates to the/usr/sbin/sellhog file and the /etc/hog file. Fileset update farm.apps.hog delivers an update to the /usr/bin/raisehog file.

Update farm.apps.hog supersedes farm.apps.hog because it delivers the same files and applies to the same level, farm.apps.hog

Update farm.apps.hog does not supersede either farm.apps.hog or farm.apps.hog because it does not contain the same files and applies to a different level, farm.apps.hog Update farm.apps.hog supersedes farm.apps.hog and farm.apps.hog


  1. hi,

    What is the major difference between aix 6.1 TL6 and TL7.
    Can't get info in google.

    1. Hi, if you go to IBM fixcentral page and choose AIX 6.1 fixpacks, you will see all the TL and SP levels. At each TL-SP there is a section called "fix details", there you will see all the enhancements and corrections.

  2. Thanks for your guidance ... have found lot of enhancements and corrections, based on your experience any specific advantage of TL7 over TL6

    1. I have no experience with TL7 (we are using TL6 and it works great).

  3. I am learning AIX. These blogs are helping a lot.... Thanks....!

  4. very nice blogs for learning.!!!

  5. will a TL update contain the fix of older TL. for example: I have AIX 6.1 TL7 SP5. It requires an APAR # XYZ. Which is present in AIX 6.1 TL7 SP7. However TL7 SP7 is not a certified version for my account I am supporting. So i have given a option to update to TL8 SP3.. Now if I do a TL upgrade to TL8, will that APAR comes by default in AIX 6.1 TL8 SPX? or do I need to first update to the TL7 SP7 and then perform an TL8 upgrade? Here APAR means solution to the problem not the problem,

  6. Hi, as TL8 SP3 is later in time than TL7 SP7, it will contain your fix...but, APAR number is TL specific, it means same apar has different numbers in each TL (don't ask me , why is it this way, IBM decided that...but for me it caused many times problems to find the same apar in different TL levels.)

  7. In the EMC storage book , it says you have to uninstall power path prior to do a AIX upgrade, is that really the case, I have EMC installed, but my rootvg is not in the hdiskpower disk , other VGs are, could you please give me your opinion on that ?? Thank you very much.

    1. Hi, I think it is a precaution from EMC side, because your current EMC version maybe not compatible with new upgraded AIX version and can cause trouble if after reboot application started automatically. If you do the upgrade with nimadm, I'm sure you can boot up to the new AIX release, just make sure application start script does not start automatically, after that you can do EMC update and after that starting applications. (Probably would be good to test this procedure on a test system first.)

    2. Thank you so much, I thought the same thing, I will ask for downtime, I will do the AIX Upgrade using nimadm or any other way , then I will ask them to bring back the database application, that way there is no other issue, I currently have EMC 5.3 in AIX 6.1 TL7SP4, I am proposing for just the AIX patches (not EMC upgrade yet) , I think I should be okay , because uninstalling/re-installing EMC could be a lot of hassle, I believe you reconfigure all the disk again after that , right? Thank you again for the suggestion , I really appreciate it.

    3. You should check if your new AIX version is compatible with your old EMC version as well. (Usually after an AIX upgrade you don't have to uninstall EMC, an update should work....but it depends on your versions.)

  8. Hi , thanks for the great post ,Could you please tell me why do we need to remove the emergency fixes and commit all the filesets before upgrading the TL.

    1. Hi, with a new TL old filesets will be replaced with noe ones. An emergency fix is just "sitting" on top of your old fileset, so a new fileset replacement is not possible if a fix is present. But starting in AIX 5.3 TL 10 and AIX 6.1 TL 3, the installp command will automatically remove an ifix from the system if you are installing the Technology Level, Service Pack, or PTF that provides the official fix for the problem, so removal will be done automatically you don't have to do it manually.

  9. what is the advantage of VTD in lunmapping,it is mondatery or with out VTD we can asigne device to the clientlpar

  10. what are the difference between AIX 5.3 and AIX 6.1?

  11. Is there a quick/easy way to get from 5.3 to 7.1?
    If so what is the step-by-step process?

  12. fileset name has last character "I" or "U", what does it indicates ?

    1. Hi, "I" means install fileset, "U" means update fileset. Update fileset can be used only if you already have and installed version, just you would like to update it to a higher version.

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  14. Hi Is there any tried and tested method for migrating/Upgrading a system from 5.2 to 6.1?

    1. Hi, I do not have a tested one, (I would try a method similar from 5.3 to 6.1)