Feature
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This feature provides a way of preventing split-brains in replica 3 gluster volumes both in time and space.
Summary
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Please see for the design discussions
Owners
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Pranith Kumar Karampuri
Ravishankar N
Current status
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Feature complete.
Code patches: and
Detailed Description
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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
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It prevents split-brains in replica 3 volumes and consumes lesser space than a normal replica 3 volume.
Scope
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### 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
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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
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Similar to a normal replica 3 volume. The only change is the syntax in
volume creation. See
Dependencies
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None
Documentation
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Status
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Feature completed. See 'Current status' section for the patches.
Comments and Discussion
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Some optimizations are under way.
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