The default data protection mechanism in Ceph is replication. It's proven and is one of the most popular methods of data protection. However, the downside of replication is that it requires double the amount of storage space to provide redundancy. For instance, if you were planning to build a storage solution with 1 PB of usable capacity with a replication factor of three, you would require 3 PB of raw storage capacity for 1 PB of usable capacity, that is, 200% or more. In this way, with the replication mechanism, the cost per GB of the storage system increases significantly. For a small cluster, you might ignore the replication overhead, but for large environments, it becomes significant.
The Firefly release of Ceph introduced another method for data protection known as erasure-coding. This method of data protection is absolutely different from the replication...