In various embodiments, methods and systems for implementing a distributed metadata management system in distributed storage systems are provided. A distributed storage system operates based on data storage resources (e.g., extents and streams). The distributed metadata management system is implemented for extent and stream metadata to facilitate the scalability of metadata processing. The distributed storage system implements extent managers and stream managers that independently manage extent and stream metadata, respectively. The extent managers are associated with an extent table that stores extent metadata. The stream managers are associated with streams that store associations with extents. The distributed metadata management system can also utilize a bootstrap layer that leverages components of a legacy distributed storage system to facilitate distributed management of extent and stream metadata. The bootstrap layer is used to store the extent table as a system table and to persist the state of the stream manager as system streams.