Part IV. Erasure Code Pools (Tech Preview)

Ceph storage strategies involve defining data durability requirements (the ability to sustain the loss of one or more OSDs without losing data). Ceph uses replicated pools by default, meaning Ceph copies every object to a primary OSD and to one or more secondary OSDs. You may specify erasure (erasure-coded pool) to save storage space. Erasure-coding will reduce the amount of disk space required to ensure data durability, but it is computationally a bit more expensive than replication.