testBNInSync(cluster, backup, 1);
// Force a roll -- BN should roll with NN.
NameNode nn = cluster.getNameNode();
NamenodeProtocols nnRpc = nn.getRpcServer();
nnRpc.rollEditLog();
assertEquals(bnImage.getEditLog().getCurSegmentTxId(),
nn.getFSImage().getEditLog().getCurSegmentTxId());
// BN should stay in sync after roll
testBNInSync(cluster, backup, 2);