Monitoring free space on OCS3 - preventing devices and bricks to get full.

Issue

You need to monitor OCS3 device usage and bricks because you can't create or expand a volume while you don't have 3 OCS devices with free space:

When creating a Heketi volume with only two nodes with the replica count set to the default value of three (replica 3), an error "No space" is displayed by Heketi as there is no space to create a replica set of three disks on three different nodes.

OCS3 - creating persistent volumes