Found while looking into T170521: deployment-logstash2 out of disk space
$ ssh deployment-eventlogging03.eqiad.wmflabs df -h Filesystem Size Used Avail Use% Mounted on udev 2.0G 12K 2.0G 1% /dev tmpfs 396M 424K 395M 1% /run /dev/vda1 18G 18G 0 100% / none 4.0K 0 4.0K 0% /sys/fs/cgroup none 5.0M 0 5.0M 0% /run/lock none 2.0G 0 2.0G 0% /run/shm none 100M 0 100M 0% /run/user /dev/mapper/vd-second--local--disk 21G 1.4G 19G 7% /srv