Scalable distributed metadata server based on nonblocking transactions

Kohei Hiraga, Osamu Tatebe, Hideyuki Kawashima

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Metadata performance scalability is critically important in high-performance computing when accessing many small files from millions of clients. This paper proposes a design of a scalable distributed metadata server, PPMDS, for parallel file systems using multiple key-value servers. In PPMDS, hierarchical namespace of a file system is efficiently managed by multiple servers. Multiple entries can be atomically updated using a nonblocking distributed transaction based on an algorithm of dynamic software transactional memory. This paper also proposes optimizations to further improve the metadata performance by introducing a server-side transaction processing, multiple readers, and a shared lock mode, which reduce the number of remote procedure calls and prevent unnecessary blocking.Performance evaluation shows the scalable performance up to 3 servers, and achieves 62,000 operations per second, which is 2.58x performance improvement compared to a single metadata performance.

Original languageEnglish
Pages (from-to)89-106
Number of pages18
JournalJournal of Universal Computer Science
Issue number1
Publication statusPublished - 2020


  • Distributed metadata server
  • Nonblocking distributed transaction
  • Parallel file system

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science(all)


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