Original link - http://michaelfranzl.com/2014/01/29/remote-server-hetzner-rebooting/

Now, in my case, I assumed that Grub2 was broken. So I activated the Hetzner Rescue System, booted into it, and reinstalled Grub2. I have found the following method here and it worked for me. First you have to mount the regular RAID filesystem under /mnt :


mount /dev/md2 /mnt
mount /dev/md1 /mnt/boot
mount -t dev -o bind /dev /mnt/dev
mount -t proc -o bind /proc /mnt/proc
mount -t sys -o bind /sys /mnt/sys
chroot /mnt



mount /dev/md2 /mnt
mount /dev/md1 /mnt/boot
mount -t dev -o bind /dev /mnt/dev
mount -t proc -o bind /proc /mnt/proc
mount -t sys -o bind /sys /mnt/sys
chroot /mnt
At this point, you are in your regular root directory. To reinstall Grub2 the Debian Way, I did:


apt-get install --reinstall grub-pc


apt-get install --reinstall grub-pc
To make really sure, I reconfigured the package:


dpkg-reconfigure grub-pc
1
dpkg-reconfigure grub-pc
It will ask you where to install the bootloader. I selected:


[*] /dev/sda
[*] /dev/sdb


[*] /dev/sda
[*] /dev/sdb
No errors were reported. I rebooted again and it did not come online immediately, for the reasons previously mentioned. I waited long enough (in my case, 15 minutes) and it did come online. So, rule number one is: Don’t panic!