My case was using VmWare as the cloud. The controllers defaulted to
10GB. I am running juju 2.3.8. I have about 12 vm's on the controller
with about 24 locally written charms. /var/lib/juju/db is currently
using 8.3GB.
The simplest solution for me was to increase the root disk size and
reboot
IIRC older Juju used the default EC2 settings, which gave 8GB hard drives,
but newer should default to 32GB disks. I'm not sure how that varies across
all providers, though.
Note that you should always be able to bootstrap with a custom root-disk
constraint. eg "juju bootstrap --bootstrap-constrai
