The storage: block declared a second osd-devices entry (loop,1024M)
               which is additive to options.osd-devices per the charm config. That
               produced 8 OSDs against expected-osd-count: 4 on ceph-mon, with
               1 GB loopback OSDs as the asymmetric secondaries - a CRUSH-weighting
               anti-pattern.

               Real production storage (DB/WAL on actual SSDs) will be declared on
               Roosevelt. For the testcloud, BlueStore co-locates DB/WAL on the data
               device which is the documented default for single-device setups.

               osd-journals is unused under BlueStore.