2.1 Definition of migration
The term migration is defined in the information technology field as the change of one operating environment for another. This can involve moving to new hardware, to new software, or both.
In the way it is used in this document, migration is defined as an upgrade of an operating system (OS), but although the words upgrade and migration are often used interchangeably, there is a difference:
An upgrade refers to an addition to an existing system. This could be the installation of a Programming Temporary Fix (PTF) or maintenance level within a particular release of AIX.
The term migration for this document means to move the software of a system environment from one AIX version or release to a different one; in our case, from AIX Version 4.3 to AIX 5L Version 5.1.
The new OS version that is installed replaces the existing operating system, removing software that is no longer used and installing new software that enhances the usability of the upgraded system. The new release also provides a new revised kernel. AIX 5L provides either
The difference between a migration and a complete overwrite installation is that the root volume group is kept with all of its file systems except /tmp, which is deleted and rebuilt while migrating.
There is a third way to install the operating system, which is the preservation installation. It only keeps the /home directory with the user files but overwrites the other file systems of the root volume group.
2.2 Reasons to migrate
This section is intended to answer the first question you should ask when we try to convince you to migrate to AIX 5L:
“This sounds like a lot of work and expense. Why should I? What’s in it for me?”
The answer has two parts:
If your environment is stable and you do not intend to make any changes or additions whatsoever in the future, you could stay with your current version of AIX. But, if you want to take advantage of the new AIX 5L function, such as online backups, a migration is worth it.
Since AIX 4.3.3 was withdrawn from marketing (WDFM) in June 2003 and from service (WDFS) December 31, 2003, there is a valid reason to migrate in a CATIA or ENOVIA environment. After December 31, 2003 there is no direct method to receive defect support.
2.3Migration methods
The following section describes the various migration methods and their advantages and disadvantages. To provide a complete overview about the migration methods, we also describe the preservation installation. Based on our customer experiences, we see the migration installation or new and complete overwrite installation as the preferred methods to move to AIX 5L.
6CATIA and Enova migration AIX 4.3 to AIX 5L Version 5.1
