> 2020/08/16 04:45:24 [ERROR] In RRD: Error updating /var/lib/munin/localdomain/localhost.localdomain-zfs_list_rpool__name-quota-g.rrd: /var/lib/munin/localdomain/localhost.localdomain-zfs_list_rpool__name-quota-g.rrd: Function update_pdp_prep, case DST_GAUGE - Cannot convert '-' to float
Used the correct munin way by soursing "$MUNIN_LIBDIR/plugins/plugin.sh" and use clean_fieldname.
For the title I removed the replacement of / by __ and on the multigraph value I added the usage of clean_fieldname to make it backwards compatible.