Give root password for mainenance
(or type Control-D to continue): _

Further, you’re not presented with any console to login and perform the manual fsck. So the only option is to do the fsck from LiveCD. Normally this is fairly simple:

sudo fsck /dev/sda1

Replace sda1 with the actual name of your partition. If you don’t know you can start the partition editor from the administration menu and check.

This is not so easy however if the partition you need to check is part of a RAID because you have to configure and start software RAID first. This is done with mdadm, however mdadm doesn’t come with the Ubuntu LiveCD.

So I ended up using a KNOPPIX LiveCD to be able to finally perform the manual fsck on my RAID partition:

• Scan the RAID partitions. You’ll also be verifying that you’re using the correct partitions that belong to a RAID.
  sudo mdadm --examine --scan /dev/sda1
sudo mdadm --examine --scan /dev/sdb1
  The output should be something like this:
  ARRAY /dev/md0 level=raid1 num-devices=2 UUID=a28090aa:6893be8b:c4024dfc:29cdb07a
• Now edit mdadm.conf:
  sudo nano /etc/mdadm/mdadm.conf
  and add the above output line to the end of the file with the following modification:
  ARRAY /dev/md0 level=raid1 num-devices=2 UUID=a28090aa:6893be8b:c4024dfc:29cdb07a devices=/dev/sda1,/dev/sdb1
  where devices=/dev/sda1,/dev/sdb1 are the two RAID partitions you want to perform the fsck
• Start the RAID setup:
  sudo /etc/init.d/mdadm start
sudo /etc/init.d/mdadm-raid start
• Perform the fsck on your RAID partition:
  sudo fsck /dev/md0
• Finally restart into your now booting Ubuntu system

Sources:

• Recover Data From RAID1 LVM Partitions With Knoppix Linux LiveCD
• Launchpad bug report