A quick way to get the total amount of provisioned space from cinder
alvaro@skyline.local: ~
$ cinder list --all-tenants
mysql like output :)
So to parse the output and add all the values in the Size col, use the next piped commands.
alvaro@skyline.local: ~
$ . admin-openrc.sh
alvaro@skyline.local: ~
$ cinder list --all-tenants | awk -F'|' '{print $6}' | sed 's/ //g' | grep -v -e '^$' | awk '{s+=$1} END {printf "%.0f", s}'
13453
The final result is in GB.