Looking to create a Software RAID 1 setup for your 2-disk server on Ubuntu Server 20.04?
Let's start with the basics: the official guide by Ubuntu (https://ubuntu.com/server/docs/installation-advanced) is outdated/wrong.
Now on to the solution:
- Select "Custom storage layout" when you reach the storage step of the installer
- If the disks have existing partitions, click on each disk under AVAILABLE DEVICES and then select REFORMAT. This will (temporarily) wipe out the partitions.