Query Answered in great details:-
1. Download the installer
2. Install with manual partitioning
- During install, at the
Partition disks step, select Manual. - If the disks contain any partitions, remove them.
- If any logical volumes are present on your drives, select
Configure the Logical Volume Manager.
- Choose
Delete logical volume until all volumes have been deleted. - Choose
Delete volume group until all volume groups have been deleted.
- If any RAID device is present, select
Configure software RAID.
- Choose
Delete MD device until all MD devices have been deleted.
- Delete every partition on the physical drives by choosing them and selecting
Delete the partition.
- Create physical partitions
- On each drive, create a 512MB partition (I’ve seen others use 128MB) at the beginning of the disk, Use as:
EFI System Partition. - On each drive, create a second partition with ‘max’ size, Use as:
Physical Volume for RAID.
- Set up RAID
- Select
Configure software RAID. - Select
Create MD device, type RAID1, 2 active disks, 0 spare disks, and select the /dev/sda2 and /dev/sdb2 devices.
- Set up LVM
- Select
Configure the Logical Volume Manager. - Create volume group
vg on the /dev/md0 device. - Create logical volumes, e.g.
swap at 16Groot at 35Gtmp at 10Gvar at 5Ghome at 200G
- Set up how to use the logical partitions
- For the
swap partition, select Use as: swap. - For the other partitions, select
Use as: ext4 with the proper mount points (/, /tmp, /var, /home, respectively).
- Select
Finish partitioning and write changes to disk. - Allow the installation program to finish and reboot.
If you are re-installing on a drive that earlier had a RAID
configuration, the RAID creation step above might fail and you never get
an md device. In that case, you may have to create a Ubuntu Live USB stick, boot into that, run gparted to clear all your partition tables, before you re-start this HOWTO.
3. Inspect system
- Check which EFI partition has been mounted. Most likely
/dev/sda1.
mount | grep boot - Check RAID status. Most likely it is synchronizing.
cat /proc/mdstat
4. Clone EFI partition
The EFI bootloaded should have been installed on /dev/sda1. As that partition is not mirrored via the RAID system, we need to clone it.
sudo dd if=/dev/sda1 of=/dev/sdb1
5. Insert second drive into boot chain
This step may not be necessary, since if either drive dies, the
system should boot from the (identical) EFI partitions. However, it
seems prudent to ensure that we can boot from either disk.
- Run
efibootmgr -v and notice the file name for the ubuntu boot entry. On my install it was \EFI\ubuntu\shimx64.efi. - Run
sudo efibootmgr -c -d /dev/sdb -p 1 -L "ubuntu2" -l \EFI\ubuntu\shimx64.efi. Depending on your shell, you might have to escape the backslashes. - Verify with
efibootmgr -v that you have the same file name for the ubuntu and ubuntu2 boot items and that they are the first two in the boot order. - Now the system should boot even if either of the drives fail!
7. Wait
If you want to try to physically remove or disable any drive to test
your installation, you must first wait until the RAID synchronization
has finished! Monitor the progress with cat /proc/mdstat However, you may perform step 8 below while waiting.
8. Remove BTRFS
If one drive fails (after the synchronization is complete), the
system will still boot. However, the boot sequence will spend a lot of
time looking for btrfs file systems. To remove that unnecessary wait,
run
sudo apt-get purge btrfs-progs
This should remove btrfs-progs, btrfs-tools and ubuntu-server. The last package is just a meta package, so if no more packages are listed for removal, you should be ok.
9. Install the desktop version
Run sudo apt install ubuntu-desktop to install the
desktop version. After that, the synchronization is probably done and
your system is configured and should survive a disk failure!
10. Update EFI partition after grub-efi-amd64 update
When the package grub-efi-amd64 is updated, the files on the EFI partition (mounted at /boot/efi)
may change. In that case, the update must be cloned manually to the
mirror partition. Luckily, you should get a warning from the update
manager that grub-efi-amd64 is about to be updated, so you don’t have to check after every update.
10.1 Find out clone source, quick way
If you haven’t rebooted after the update, use
mount | grep boot
to find out what EFI partition is mounted. That partition, typically /dev/sdb1, should be used as the clone source.
10.2 Find out clone source, paranoid way
Create mount points and mount both partitions:
sudo mkdir /tmp/sda1 /tmp/sdb1
sudo mount /dev/sda1 /tmp/sda1
sudo mount /dev/sdb1 /tmp/sdb1
Find timestamp of newest file in each tree
sudo find /tmp/sda1 -type f -printf '%T+ %p\n' | sort | tail -n 1 > /tmp/newest.sda1
sudo find /tmp/sdb1 -type f -printf '%T+ %p\n' | sort | tail -n 1 > /tmp/newest.sdb1
Compare timestamps
cat /tmp/newest.sd* | sort | tail -n 1 | perl -ne 'm,/tmp/(sd[ab]1)/, && print "/dev/$1 is newest.\n"'
Should print /dev/sdb1 is newest (most likely) or /dev/sda1 is newest. That partition should be used as the clone source.
Unmount the partitions before the cloning to avoid cache/partition inconsistency.
sudo umount /tmp/sda1 /tmp/sdb1
10.3 Clone
If /dev/sdb1 was the clone source:
sudo dd if=/dev/sdb1 of=/dev/sda1
If /dev/sda1 was the clone source:
sudo dd if=/dev/sda1 of=/dev/sdb1
Done!
/*_*\
Success rate upto 90% as per Niclas Börlin’s answer @askubuntu.
