- Operating system, patch and compiler prerequisites for the new IDS version
- Instructions for correctly backing up and shutting down your IDS instance prior to upgrading
- Release notes and machine notes for the version you are upgrading to
- Knowledge of new features implemented since your last release that might be useful to you
- Understanding of how to optimally tune your onconfig file and other settings for the new release
A recent Informix Technote attempts to consolidate some of this information: Knowledge Collection: IBM Informix Dynamic Server (IDS) version 11.10 Migration.
The article includes a presentation on Conversion/Reversion by Nelson Corcoran which provides a very useful summary of pre and post conversion steps and reversion caveats. It also goes into some of the internal details of how conversion works during an upgrade.
Note: this document is part of a wider set of documents on migration that starts here: http://www-1.ibm.com/support/docview.wss?uid=swg21259394.
What else should IBM provide to make migration to a later release of IDS more straightforward?
I'm going to try re-enabling comments on this blog for a while and see how the spam goes so if you have any suggestions please do leave a comment.
Disabling the Installation's Database Server Prerequisites Check
The IDS 11.10.xC2 Documentation Notes mention a new feature that allows you to disable the standard OS version and shared library checks made by the IDS installer. I am already finding this feature useful since I have a machine with an older version of Solaris (2.8) and -disable-checks saves me from having to hack the installer just to install IDS.
Here is an extract from the documentation:
A -disable-checks option has been added to the Dynamic Server installation command. This option lets the install application run without verifying that your computer has the prerequisites for a working instance. The database server prerequisites are listed in Platform.prq on an operating system basis. Use the -disable-checks option to bypass the shared-library prerequisites check.
To use a java command to start the Dynamic Server installation, disable the shared-libraries check by using the -W systemcheck.active=false option in your command.
Refer to the Machine Notes for comprehensive operating system information.
One word of warning - the prerequisite checks are there for a reason; the check is for the minimum OS and library versions that IDS underwent comprehensive testing for on that platform. Installing on an older OS is at your own risk, but can be useful in known situations to make the upgrade process smoother.