根據掛載目錄
(node_filesystem_size_bytes {mountpoint ="/"} - node_filesystem_free_bytes {mountpoint ="/"}) /
node_filesystem_size_bytes {mountpoint ="/"} * 100
根據盤符報警
(node_filesystem_size_bytes {device=~"/dev/vd[a-z]1"} - node_filesystem_free_bytes {device=~"/dev/vd[a-z]1"}) /
node_filesystem_size_bytes {device=~"/dev/vd[a-z]1"} * 100