AIS v3.9 is substantial productization and performance-improving release. Much of the codebase has been refactored for consistency, with micro-optimization and stabilization fixes across the board.


  • promote: redefine to handle remote file shares; collaborate when promoting via entire cluster; add usability options; productize;
  • xmeta: extend to also dump in a human-readable format: a) erasure-coded metadata and b) object metadata;
  • memory usage and fragmentation: consistently use mem-pooling (via sync.Pool) for all control structures in the datapath;
  • optimistic concurrency when running batch prefetch jobs; refactor and productize;
  • optimize PUT datapath;
  • core logic to deconflict running concurrent xactions (asynchronous jobs): bucket rename vs bucket copy, put a node into maintenance mode vs offline ETL, and similar;
  • extend and reinforce resilvering logic to withstand simultaneous disk losses/attachments - at runtime and with no downtime;
  • stabilize global rebalance to successfully pass multiple hours of random node “kills” and restarts - node-left and node-joined events - in presence of stressful data traffic;
  • self-healing: object metadata cache to support recovery upon mountpath events (e.g., drive failures);
  • error handling: phase out generic fmt.Errorf and consistently use assorted error types instead;
  • additional options to speedup listing of very large buckets (list-objects);
  • numerous micro-optimizing improvements: fast datapath query (DPQ) and many more.