Comment 2 for bug 95704

Yep, I can confirm this. I just got a brand new nicely equipped machine to use as an all purpose server and since I have the time, I thought I would play around with the new Feisty beta1 on it. Preferred combo of software raid1 and raid5 produced the same results as the previous posters. Afterward I grabbed the server install disk for Dapper and Edgy and didn't have any problems at all with them.

I did stumble upon a workaround for this problem though. After you partition up the hdds as necessary and then choose the Software Raid option at the top of the screen you are prompted to confirm your choice. After confirming you are taken to the "Create MD / Delete MD" screen. At that point before completing that screen, if you back all the way out and abort the installation, reboot, and go back repeating all of the steps to get to the partition section, the installation will proceed smoothly from there. I did this several times while trying to figure things out and this workaround works every time.

Even though the installation completed normally after that, things are still wrong with this RAID. But that's for another bug.