Feature ------- This feature provides a way of preventing split-brains in replica 3 gluster volumes both in time and space. Summary ------- Please see for the design discussions Owners ------ Pranith Kumar Karampuri Ravishankar N Current status -------------- Feature complete. Code patches: and Detailed Description -------------------- Arbiter volumes are replica 3 volumes where the 3rd brick of the replica is automatically configured as an arbiter node. What this means is that the 3rd brick will store only the file name and metadata, but does not contain any data. This configuration is helpful in avoiding split-brains while providing the same level of consistency as a normal replica 3 volume. Benefit to GlusterFS -------------------- It prevents split-brains in replica 3 volumes and consumes lesser space than a normal replica 3 volume. Scope ----- ### Nature of proposed change ### Implications on manageability None ### Implications on presentation layer None ### Implications on persistence layer None ### Implications on 'GlusterFS' backend None ### Modification to GlusterFS metadata None ### Implications on 'glusterd' None How To Test ----------- If we bring down bricks and perform writes in such a way that arbiter brick is the only source online, writes/reads will be made to fail with ENOTCONN. See 'tests/basic/afr/arbiter.t' in the glusterfs tree for examples. User Experience --------------- Similar to a normal replica 3 volume. The only change is the syntax in volume creation. See Dependencies ------------ None Documentation ------------- --- Status ------ Feature completed. See 'Current status' section for the patches. Comments and Discussion ----------------------- Some optimizations are under way. ---