The CRUSH Hierarchy
Ceph Monitor Nodes (MONs) stores the cluster's state in the form of a map. This map is composed of devices and buckets. Each device and bucket is assigned a unique identifier and weight. The collected set of devices and buckets is known as the cluster map or CRUSH map. Buckets are hierarchical. They contain devices or other buckets, allowing them to act as interior nodes in the storage hierarchy while devices are always leaves, with the top bucket of the hierarchy known as the root. As OSDs are deployed Ceph assigns an initial weight to each OSD, typically based on the capacity of the drive on which it lives. Bucket weights are calculated as the sum of the weights of all the internal buckets or devices they contain. Administrators ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access