first full-sync

On drupal-dev (rentre.tld):

#if it exists
lvremove all/drupal-dev-snapshot
#Create the snapshot
#Before doing this, ensure nobody is working on the vm
#It will take only a few seconds, then people can continue to use the vm
lvcreate -L1G -s -n drupal-dev-snapshot /dev/all/drupal-dev

On z2 ganeti master :

#We supposed a drupal-clone vm is created, 10G disk
ganeti-master:~# gnt-instance shutdown drupal-clone.vm.gnt
#Ganeti will print some path informations after this command
ganeti-master:~# gnt-instance activate-disks drupal-clone.vm.gnt
# ganeti output : z2-4.host.gnt:disk/0:/dev/drbd8

On z2 instance's primary node (z2-4 in previous example):

z2-4:~# ssh root@rentre.tld "dd if=/dev/all/drupal-dev-snapshot" | dd of=/dev/drbd8
z2-4:~# kpartx -dv /dev/drbd8

On z2 ganeti master :

ganeti-master:~# gnt-instance deactivate-disks drupal-clone.vm.gnt

sync existing vm with rsync

On z2 ganeti master :

#We supposed a drupal-clone vm is created, 10G disk
ganeti-master:~# gnt-instance shutdown drupal-clone.vm.gnt
#Ganeti will print some path informations after this command
ganeti-master:~# gnt-instance activate-disks drupal-clone.vm.gnt
# ganeti output : z2-4.host.gnt:disk/0:/dev/drbd8

On z2 instance's primary node (z2-4 in previous example), first make sure with vgs that there is no "debian" group active already.

z2-4:~# mkdir /mnt/drupal-clone
z2-4:~# kpartx -av /dev/drbd8
z2-4:~# vgscan 
z2-4:~# vgchange -ay
z2-4:~# mount /dev/debian/root /mnt/drupal-clone/
#assuming you put the ssh key on drupal-dev.rentre.tld
#no need to sync /boot which is mounted on another partition
z2-4:~# rsync --delete  --numeric-ids -avHz --exclude=*.iso --exclude=/proc --exclude=/boot --exclude=/sys root@drupal-dev.rentre.tld:/ /mnt/drupal-clone/ > /root/drupal-clone.log 2>&1
z2-4:~# umount /mnt/drupal-clone
z2-4:~# vgchange -an
z2-4:~# kpartx -dv /dev/drbd8

On z2 ganeti master :

ganeti-master:~# gnt-instance deactivate-disks drupal-clone.vm.gnt