then formated /dev/md0 with ext4 file system, because Ubiquity doesn't allow to choose md0 until it's formated with filesystem
2. In Ubiquity step "Downloading language packages" (In Lithuanian - "Atsiunčiami kalbos paketai") I installed mdadm in target system with these commands:
Ubuntu 12.04 Desktop can be installed into Linux Software RAID (md) storage with these steps:
1. I've installed mdadm in live system, then created Linux Software RAID with this command:
sudo mdadm --create /dev/md0 --level=1 --raid-disks=2 /dev/sda1 /dev/sdb1
then formated /dev/md0 with ext4 file system, because Ubiquity doesn't allow to choose md0 until it's formated with filesystem
2. In Ubiquity step "Downloading language packages" (In Lithuanian - "Atsiunčiami kalbos paketai") I installed mdadm in target system with these commands:
sudo cp /var/cache/ apt/archives/ mdadm_3. 2.3-2ubuntu1_ i386.deb /target/ var/cache/ apt/archives/ apt/archives/ mdadm_3. 2.3-2ubuntu1_ i386.deb
sudo chroot /target/ dpkg -i /var/cache/