When creating a Ceph Pool (
OP-80), it should be possible to create a so-called "Erasure-coded pool":
"Erasure-coded pools require less storage space compared to replicated pools. The erasure-coding support has higher computational requirements and only supports a subset of the operations allowed on an object (for instance, partial write is not supported)."
See http://ceph.com/docs/firefly/dev/erasure-coded-pool/ for more details.
This blog post also provides some useful background information.