Ozone namespace concepts
The Ozone namespace includes the following conceptual entities: volumes, keys, and buckets. Each key is part of a bucket, which, in turn, belongs to a volume. Only an administrator can create volumes. Depending on their requirements, regular users can create buckets in volumes. Ozone stores data as keys inside these buckets.
- An Ozone volume is similar to a user account, for example; sales, marketing, engineering, and so on.
- An Ozone bucket is similar to a directory or an Amazon S3 bucket. A bucket any number of keys but cannot contain other buckets.
- An Ozone key is similar to any key in an object store or a file in a filesystem. If a key is used as a filesystem, the prefixes are treated as directories.
When a client writes a key, Ozone stores the associated data on DataNodes in chunks called blocks. Therefore, each key is associated with one or more blocks. Within a DataNode, multiple unrelated blocks can reside in a storage container. Storage container is an internal Ozone abstraction that represents a collection of blocks and that singularly forms the unit of replication in Ozone.