To get objects' metadata and system information, the S3 GW makes requests to the Tree service. This is a service in NeoFS storage that keeps different information as a tree structure.
Each node keeps one of the types of data as a set of key-value pairs:
- Bucket settings: lock configuration and versioning mode
- Bucket tagging
- Object tagging
- Object metadata: OID, name, creation time, system metadata
- Object locking settings
- Active multipart upload info
Some data takes up a lot of memory, so we store it in NeoFS nodes as an object with payload. But we keep these objects' metadata in the Tree service too:
- Notification configuration
- CORS
- Metadata of parts of active multipart uploads