Mastering Proxmox - Third Edition

Ceph components summary

If we want to understand the relationship between all the Ceph components we have seen so far, we can think of it this way: each pool comprises multiple PGs. Each PG comprises multiple OSDs. An OSD map keeps track of the number of OSDs in the cluster and in the nodes they are in. The mon map keeps track of the number of monitors in a cluster to form a quorum and maintains a master copy of the cluster map. A CRUSH map dictates how much data needs to be written to an OSD and how to write or read it. These are the building blocks of a Ceph cluster. The following diagram is an example of how the Ceph components come together to form the storage system: