OVH Rescue in RAM

cd /var
rm lib && rsync -av /nfs/var/lib /var/
rm cache && rsync -av /nfs/var/cache /var/
cd /
mv usr usr2
/usr2/bin/rsync -av /nfs/usr /

Finally we can install anything in RAM, like a live USB!

Update: No more necessary with latest OVH rescue!