Is ext4 ready for production usage in debian 5 (with linux kernel version 2.6.26) ? Will it be stable, oops-free and bug-free?
Unfortunatly, not yet :-(. That's why you don't find it when you try to install a Debian with the installer.
You need to upgrade to Squeeze (testing version) if you want it as you will got a newer kernel (improving stability). 2.6.26 kernel is quiet old now and wasn't stable enough to have it in production.
You may look at Lenny and a Half, this avoid you to use a testing version, and you'll have newer kernel and ext4 binaries to have it stable.
Another solution, is the backuports, but I'm not sure if a newer kernel is available.
And finally if you want to have ext4 in production, you should have a kernel version equal or upper than 2.6.28 ( http://en.wikipedia.org/wiki/Ext4 )
You will not find ext4 support with the debian lenny standard 2.6.26 kernel, but you can grab 2.6.30 from the backports project http://www.backports.org/.
IMHO, using XFS is a better choice, EXT4 is still not too stable (even if Google is migrating to it :))) )
Yep it's ready, but not easily available in the installer. I've installed many computers using a custom installer kmuto with the following layout:
And it works great.
It works just fine.