Check RAID status on Ubuntu

Check RAID status:

/sbin/mdadm --detail /dev/md0

Or check with this:

sudo cat /proc/mdstat

This is what a good status will look like:

Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] 
md1 : active raid1 sdb5[0] sdc5[1]
      1485888 blocks [2/2] [UU]
      
md0 : active raid1 sdb1[0] sdc1[1]
      242709888 blocks [2/2] [UU]
      
unused devices:

The [UU] (I think) indicates the status of both drives in the array, and both are Up

Easy steps for Ubuntu server upgrade

sudo apt-get update
sudo apt-get upgrade

Edit /etc/update-manager/release-upgrades, and ensure:

Prompt=normal

(otherwise if its LTS you will only be able to upgrade to the next LTS release if one is available

sudo apt-get install update-manager-core
sudo do-release-upgrade

…and follow the prompts.