Login to Remote-Console first, so you can see boot messages, … and kernel panics, if unlucky

Re-Install takes 1h

Set Boot mode to recovery in “RecoveryManager” at https://config.stratoserver.net/ Wait for 15-20min!! until “ServerData” Serverstatus shows: Installation finished

Strato sets RAIDs to /md/126 and md127 - that sucks! - via grub install, …,.. you can mess up the system

log in to recovery via

ssh root@IP   # recovery root passwd is shown in "Serverdata"

mount /dev/md127 /mnt/    # system partition
mount /dev/md126 /mnt/boot/    # boot partition

to re-install grub, you need to chroot

mount -o bind /dev /mnt/dev
mount -t proc none  /mnt/proc/
mount -t sysfs none /mnt/sys

chroot /mnt
update-grub

( grub-mkdevicemap  #  In case of error “no such disc” )

grub-install /dev/sda
grub-install /dev/sdb

To exit the recovery console you need to set boot mode to normal and wait 10min until “ServerData” Serverstatus shows: Installation finished

You need to setup your ssh key in the webmanager to enter in rescue mode without password! the password will be sent by mail as well.

- Change netboot mode in web-manager: set to “rescue” - Click “reboot”

Mount partitions:

mkdir /mnt/md2
mount /dev/md2 /mnt/md2/

After restore, click “netboot” in webmanager again and reset it to “harddisc”

If the system does not boot anymore, you can open the encrypted device anyway with a live system on USB stick or CD.

# find the correct partitions:
fdisk -l 

# open the container 
# "sdb5_crypt" is just an example. **Check what's written in /etc/crypttab - the names must match!**
cryptsetup luksOpen /dev/sdXY sdXY_sdb5_crypt

# activate the LVM volume group (if you use LVM2):
vgchange -ay

# find new volume groups in /dev/mapper/ and mount them (maybe it's just root or home, var, ...might be in, too):
mount /dev/mapper/ubuntu--vg-root /mnt

# mount the unencrypted boot parti:
mount /dev/sdXZ /mnt/boot

# bind mount some important dirs:
mount -t proc proc /mnt/proc
mount -o bind /dev /mnt/dev
mount -t sysfs none /mnt/sys

Now you can take your data back already.

To repair what is broken, you probably need to change root into that system:

chroot /mnt

All following commands are executed inside the broken system. Some hints for repairs:

apt install lvm2 cryptsetup-initramfs    # debian uninstalled lvm during an upgrade :(

If your root system is BTRFS, you need btrfs-progs and the kernel module during the early initramfs boot stage:

apt install btrfs-progs

Add a missing module to initramfs - inside the chroot:

mcedit /etc/initramfs-tools/modules

Write one module name like “btrfs” per line.

Then regenerate the initramfs for all installed kernels:

update-initramfs -u -k all

* Check that the name in /etc/crypttab is the same as in the cryptsetup luksOpen Command, usually something like sda5_crypt * Also check the UUID entries in /etc/crypttab compared to ls -la /dev/disk/by-uuid/

TbC.. There may be various other reasons for bootproblems…

• really helpul! https://feeding.cloud.geek.nz/posts/recovering-from-unbootable-ubuntu-encrypted-lvm-root-partition/
• various other hints https://askubuntu.com/questions/567730/gave-up-waiting-for-root-device-ubuntu-vg-root-doesnt-exist#567897