I see no sense in a backup strategy which only works when the stack is down. Avoid the double-compression implicit in the scripts supplied with SensorsIot/IOTstack: An InfluxDB backup produces .tar.gz ...

$ sudo stat -c "%s" /var/lib/docker/containers/881426b293bf53b2cc32ac333d674b91d389e74f336700fd0a5f3d4ad01777da ...