I think this node is used for caching castor jobs.
thcipriani@castor02:~$ df -h Filesystem Size Used Avail Use% Mounted on udev 10M 0 10M 0% /dev tmpfs 1.6G 153M 1.5G 10% /run /dev/vda3 19G 3.4G 15G 19% / tmpfs 4.0G 0 4.0G 0% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 4.0G 0 4.0G 0% /sys/fs/cgroup /dev/mapper/vd-second--local--disk 60G 55G 1.7G 98% /srv