Hierarchical NameSpace (HNS), abbreviated as hierarchical bucket, is a brand-new bucket type introduced by TOS Object Storage that is based on hierarchical metadata management. Besides its hierarchical namespace features, a HNS bucket can scale as much as a FNS bucket. It also delivers seamless interoperability between object and file semantics. This allows data to be accessed through multiple protocols, so you can process data more efficiently.

Compared to the original flat namespace (FNS, Flat NameSpace, also known as flat bucket), this approach provides strong support for directory-level mv and rename operations, while also optimizing common read operations such as List and directory Head. These enhancements improve data processing efficiency and performance, making it well suited to usage scenarios in big data, data lake, and AI fields.

This document describes how to use the TOS Java SDK listBuckets interface to enumerate the hierarchical namespace lists for all regions under your account.