[HBASE-11405] Multiple invocations of hbck in parallel disables balancer permanently

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.99.0
• Fix Version/s: 0.98.7, 0.94.24, 0.99.1
• Component/s: Balancer, hbck
• Hadoop Flags: Reviewed
• Assignee: Bharath Vissapragada
• Reporter: Bharath Vissapragada
• Created: 24/Jun/14 05:39
• Updated: 06/Apr/18 17:55
• Resolved: 25/Sep/14 16:48

Description

This is because of the following piece of code in hbck

  boolean oldBalancer = admin.setBalancerRunning(false, true);
    try {
      onlineConsistencyRepair();
    }
    finally {
      admin.setBalancerRunning(oldBalancer, false);
    }

Newer invocations set oldBalancer to false as it was disabled by previous invocations and this disables balancer permanently unless its manually turned on by the user. Easy to reproduce, just run hbck 100 times in a loop in 2 different sessions and you can see that balancer is set to false in the HMaster logs.

Issue Links

• links to: reviewboard