Install Ubuntu 14.04.3 server in software RAID1 configuration

I found many guides on this topic, yet they  were somehow obsolete as disk partitioning procedure seemed to have changed  since 14.04.3 version of the server.

So here is my guide to install Ubuntu  14.04.3 server in a RAID1 configuration (two hdd in mirroring). The guide is made in a virtual machine with 2X8 GB disks, sda and sdb. In your case you will have  at least two real hdd with your specific capacity. Hdd technology is not  relevant, could be two classical hdd or two SSD drives.

It is also assumed that the two drives have  the same capacity; otherwise, additional manual activity is necessary to adapt partition sizes.

So, burn the Ubuntu 14.04.3 server image to  a CD or transfer it to a bootable media and start the installation until you
get to the disks partitioning:

Go to manual partitioning:

You will see the two hdd devices, sda and  sdb. Select sda and clic enter :

Go to <Yes> to approve that the all  size is used for partitioning.

Select then sdb device and do the same:

Select the free space of drive sda for  partitioning:

Choose 'Automatically partition the free space' to do the partitioning:

Then finish the partitioning and write changes to disk:

Now select the free space of drive sdb for partitioning:

Choose 'Automatically partition the  free space' to do the partitioning:

Finish partitioning of drive sdb and write changes to disk.

Now is time to configure the software raid  and create the md devices. In our configuration, we will have two md devices,  one for each partition created previously on both disks.

Select 'Configure software RAID':

Write changes before creating md devices.

Select RAID1:

Set the number of active devices (2 for RAID1):

Set the number of spare devices (0 in my  case):

Choose the partitions to build the first md  device:

Write changes to disk:

Do the same steps for the remaining md devices to create:

Finish the md devices creation:

Now is time to configure the partitions of md (RAID) devices; go to the partition of the first RAID device:

Setup 'Use as' as EXT4 file system:

Go to the mount point and choose root mount  point:

We are done with the setting up of this  partition.

Now setup the second partition on the next  md device as swap area:

Use the partition as swap area:

We are done with the md devices partitions  setup.

Partitioning is finished; write changes on  the disk.

After this step, installation continues. At  this stage, we set up two software RAID devices for the two partitions in RAID1 configuration  with two physical disks. Select all the options you want during the installation.

Later, before finishing the server  installation, the installer will ask for the creation of the boot loader:

Choose <Yes> for the creation of the  boot loader.

You are done.

Congratulation, you have a functional Ubuntu  14.04.3 server installed in software RAID1 (disk mirroring) configuration.

Warning: at boot you will have this warning  message:

Without any key pressing, system boot will resume after few seconds and system loads correctly in RAID1 configuration.

This warning is a low severity bug in the  grub loader with RAID partitions (see the bug details).