https://medium.com/@texasdave2/the-last-grafana-boom-table-plugin-tutorial-youll-ever-need-46d26f67c0f5

100 - ((node_filesystem_avail_bytes{instance=~"$node:$port",job=~"$job",mountpoint=~"/mnt/data-.*",fstype!="rootfs"} * 100) / node_filesystem_size_bytes{instance=~"$node:$port",job=~"$job",mountpoint=~"/mnt/data-.*",fstype!="rootfs"})

thresholds 10,20,30,40,50,60,70,80,90

transform values _fa-square,green,1_ _fa-square,gray,9_|_fa-square,green,2_ _fa-square,gray,8_|_fa-square,green,3_ _fa-square,gray,7_|_fa-square,green,4_ _fa-square,gray,6_|_fa-square,yellow,5_ _fa-square,gray,5_|_fa-square,yellow,6_ _fa-square,gray,4_|_fa-square,yellow,7_ _fa-square,gray,3_|_fa-square,red,8_ _fa-square,gray,2_|_fa-square,red,9_ _fa-square,gray,1_|_fa-square,red,10_ _fa-square,gray,0_