IBM has a RedBook out which covers configuration of Informix, called Customising Informix for your Environment. Chapters include:

Optimizing IDS for your environment
Enterprise data availability
The administration free zone
Easing into extensibility
Taking advantage of database events

I will be reviewing this RedBook in more detail shortly.

IBM has a RedBook out, called Advanced Functionality for Modern Business, on the functions that make IDS 11 fit modern business requirements better, including chapters on:

Fast implementation
Configuration
Enhancements in high availability
Data privacy
Easy administration and the administrative API
SQL query drill-down
Functional extensions to IDS
Development tools, interfaces, and SOA integration

I wish people made more use of functional extensions to IDS: it's not difficult and it adds immense power to your s

An issue I bumped into two weeks ago.
Opened a call with IBM, but didn't go further than being pointed to Documentation Notes, which is fine, but I'd still prefer to know why.

A simple table with one varchar field:

Load it with records of varying real length (approx. 60000 rows in my case), then do:

So, this is just lengthening of varchar field definition, not the data itself.

If you're careful enough (which I wasn't) you'll notice it takes some time to execute the statement, it uses a lot (depending on number of rows, of course) of dbspace in which the table is created and logical log space.

Motivated by article on using Xen and Informix on Developerworks (http://www.ibm.com/developerworks/db2/library/techarticle/dm-0807fuerderer/index.html) and by Eric's comment I'll try to give a similar step-by-step explanation on how to setup KVM virtual machines on Linux box if you need a playground to test new features or proof-of-concept projects. Originally, I commented it seems easier to setup KVM than Xen, and hopefully I'll show it is. Except maybe for one bit :) And that's networking. More on that later. I'm assuming the next hardware configuration: