[2014-11-11 11:55:29,701] ERROR com.google.gerrit.server.git.ChangeMergeQueue : Merge attempt for TestRepoAaron,refs/heads/master failed
com.google.gerrit.server.git.MergeException: Cannot update refs/heads/master
    at com.google.gerrit.server.git.MergeOp.updateBranch(MergeOp.java:645)
    at com.google.gerrit.server.git.MergeOp.merge(MergeOp.java:252)
    at com.google.gerrit.server.git.ChangeMergeQueue$2.call(ChangeMergeQueue.java:210)
    at com.google.gerrit.server.git.ChangeMergeQueue$2.call(ChangeMergeQueue.java:207)
    at com.google.gerrit.server.util.RequestScopePropagator$5.call(RequestScopePropagator.java:222)
    at com.google.gerrit.server.util.RequestScopePropagator$4.call(RequestScopePropagator.java:201)
    at com.google.gerrit.server.git.PerThreadRequestScope$Propagator$1.call(PerThreadRequestScope.java:75)
    at com.google.gerrit.server.git.ChangeMergeQueue.mergeImpl(ChangeMergeQueue.java:207)
    at com.google.gerrit.server.git.ChangeMergeQueue.access$200(ChangeMergeQueue.java:54)
    at com.google.gerrit.server.git.ChangeMergeQueue$MergeEntry.run(ChangeMergeQueue.java:250)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
    at com.google.gerrit.server.git.WorkQueue$Task.run(WorkQueue.java:364)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    at java.lang.Thread.run(Thread.java:722)
Caused by: java.io.IOException: Failure to replicate update. Output is:
GitMS - minimum number of learners not available
    at org.eclipse.jgit.lib.RefUpdate.doReplicatedUpdate(RefUpdate.java:769)
    at org.eclipse.jgit.lib.RefUpdate.update(RefUpdate.java:508)
    at com.google.gerrit.server.git.MergeOp.updateBranch(MergeOp.java:611)
    ... 18 more