Merge "Add more info to ShardStats JXM bean"
[controller.git] / opendaylight / md-sal / sal-akka-raft / src / main / java / org / opendaylight / controller / cluster / raft / RaftActor.java
index a7c3db4fc246bcce77d23e8d324a4301d930568e..9faffb9395dcdb98d02951e7e9530d1ac602b3f5 100644 (file)
@@ -10,8 +10,6 @@ package org.opendaylight.controller.cluster.raft;
 
 import akka.actor.ActorRef;
 import akka.actor.ActorSelection;
-import akka.event.Logging;
-import akka.event.LoggingAdapter;
 import akka.japi.Procedure;
 import akka.persistence.RecoveryCompleted;
 import akka.persistence.SaveSnapshotFailure;
@@ -21,28 +19,38 @@ import akka.persistence.SnapshotSelectionCriteria;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Optional;
 import com.google.common.base.Stopwatch;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
 import com.google.protobuf.ByteString;
 import java.io.Serializable;
+import java.util.Collection;
+import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
+import org.apache.commons.lang3.time.DurationFormatUtils;
 import org.opendaylight.controller.cluster.DataPersistenceProvider;
 import org.opendaylight.controller.cluster.common.actor.AbstractUntypedPersistentActor;
 import org.opendaylight.controller.cluster.notifications.RoleChanged;
+import org.opendaylight.controller.cluster.raft.base.messages.ApplyJournalEntries;
 import org.opendaylight.controller.cluster.raft.base.messages.ApplyLogEntries;
 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
-import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
 import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
+import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader;
 import org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior;
 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
-import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
+import org.opendaylight.controller.cluster.raft.client.messages.FollowerInfo;
+import org.opendaylight.controller.cluster.raft.client.messages.GetOnDemandRaftState;
+import org.opendaylight.controller.cluster.raft.client.messages.OnDemandRaftState;
 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
-import org.opendaylight.controller.protobuff.messages.cluster.raft.AppendEntriesMessages;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * RaftActor encapsulates a state machine that needs to be kept synchronized
@@ -85,8 +93,17 @@ import org.opendaylight.controller.protobuff.messages.cluster.raft.AppendEntries
  * </ul>
  */
 public abstract class RaftActor extends AbstractUntypedPersistentActor {
-    protected final LoggingAdapter LOG =
-        Logging.getLogger(getContext().system(), this);
+
+    private static final long APPLY_STATE_DELAY_THRESHOLD_IN_NANOS = TimeUnit.MILLISECONDS.toNanos(50L); // 50 millis
+
+    private static final Procedure<ApplyJournalEntries> APPLY_JOURNAL_ENTRIES_PERSIST_CALLBACK =
+            new Procedure<ApplyJournalEntries>() {
+                @Override
+                public void apply(ApplyJournalEntries param) throws Exception {
+                }
+            };
+
+    protected final Logger LOG = LoggerFactory.getLogger(getClass());
 
     /**
      * The current state determines the current behavior of a RaftActor
@@ -98,7 +115,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
      * This context should NOT be passed directly to any other actor it is
      * only to be consumed by the RaftActorBehaviors
      */
-    private final RaftActorContext context;
+    private final RaftActorContextImpl context;
 
     /**
      * The in-memory journal
@@ -107,14 +124,10 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
 
     private CaptureSnapshot captureSnapshot = null;
 
-    private volatile boolean hasSnapshotCaptureInitiated = false;
-
     private Stopwatch recoveryTimer;
 
     private int currentRecoveryBatchCount;
 
-
-
     public RaftActor(String id, Map<String, String> peerAddresses) {
         this(id, peerAddresses, Optional.<ConfigParams>absent());
     }
@@ -131,8 +144,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
 
     private void initRecoveryTimer() {
         if(recoveryTimer == null) {
-            recoveryTimer = new Stopwatch();
-            recoveryTimer.start();
+            recoveryTimer = Stopwatch.createStarted();
         }
     }
 
@@ -144,6 +156,19 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         super.preStart();
     }
 
+    @Override
+    public void postStop() {
+        if(currentBehavior != null) {
+            try {
+                currentBehavior.close();
+            } catch (Exception e) {
+                LOG.debug("{}: Error closing behavior {}", persistenceId(), currentBehavior.state());
+            }
+        }
+
+        super.postStop();
+    }
+
     @Override
     public void handleRecover(Object message) {
         if(persistence().isRecoveryApplicable()) {
@@ -152,7 +177,10 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
             } else if (message instanceof ReplicatedLogEntry) {
                 onRecoveredJournalLogEntry((ReplicatedLogEntry) message);
             } else if (message instanceof ApplyLogEntries) {
-                onRecoveredApplyLogEntries((ApplyLogEntries) message);
+                // Handle this message for backwards compatibility with pre-Lithium versions.
+                onRecoveredApplyLogEntries(((ApplyLogEntries) message).getToIndex());
+            } else if (message instanceof ApplyJournalEntries) {
+                onRecoveredApplyLogEntries(((ApplyJournalEntries) message).getToIndex());
             } else if (message instanceof DeleteEntries) {
                 replicatedLog.removeFrom(((DeleteEntries) message).getFromIndex());
             } else if (message instanceof UpdateElectionTerm) {
@@ -172,16 +200,14 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
 
                 onRecoveryComplete();
 
-                RaftActorBehavior oldBehavior = currentBehavior;
-                currentBehavior = new Follower(context);
-                handleBehaviorChange(oldBehavior, currentBehavior);
+                initializeBehavior();
             }
         }
     }
 
     private void onRecoveredSnapshot(SnapshotOffer offer) {
         if(LOG.isDebugEnabled()) {
-            LOG.debug("SnapshotOffer called..");
+            LOG.debug("{}: SnapshotOffer called..", persistenceId());
         }
 
         initRecoveryTimer();
@@ -197,38 +223,37 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         context.setLastApplied(snapshot.getLastAppliedIndex());
         context.setCommitIndex(snapshot.getLastAppliedIndex());
 
-        Stopwatch timer = new Stopwatch();
-        timer.start();
+        Stopwatch timer = Stopwatch.createStarted();
 
         // Apply the snapshot to the actors state
-        applyRecoverySnapshot(ByteString.copyFrom(snapshot.getState()));
+        applyRecoverySnapshot(snapshot.getState());
 
         timer.stop();
         LOG.info("Recovery snapshot applied for {} in {}: snapshotIndex={}, snapshotTerm={}, journal-size=" +
                 replicatedLog.size(), persistenceId(), timer.toString(),
-                replicatedLog.snapshotIndex, replicatedLog.snapshotTerm);
+                replicatedLog.getSnapshotIndex(), replicatedLog.getSnapshotTerm());
     }
 
     private void onRecoveredJournalLogEntry(ReplicatedLogEntry logEntry) {
         if(LOG.isDebugEnabled()) {
-            LOG.debug("Received ReplicatedLogEntry for recovery: {}", logEntry.getIndex());
+            LOG.debug("{}: Received ReplicatedLogEntry for recovery: {}", persistenceId(), logEntry.getIndex());
         }
 
         replicatedLog.append(logEntry);
     }
 
-    private void onRecoveredApplyLogEntries(ApplyLogEntries ale) {
+    private void onRecoveredApplyLogEntries(long toIndex) {
         if(LOG.isDebugEnabled()) {
-            LOG.debug("Received ApplyLogEntries for recovery, applying to state: {} to {}",
-                    context.getLastApplied() + 1, ale.getToIndex());
+            LOG.debug("{}: Received ApplyLogEntries for recovery, applying to state: {} to {}",
+                    persistenceId(), context.getLastApplied() + 1, toIndex);
         }
 
-        for (long i = context.getLastApplied() + 1; i <= ale.getToIndex(); i++) {
+        for (long i = context.getLastApplied() + 1; i <= toIndex; i++) {
             batchRecoveredLogEntry(replicatedLog.get(i));
         }
 
-        context.setLastApplied(ale.getToIndex());
-        context.setCommitIndex(ale.getToIndex());
+        context.setLastApplied(toIndex);
+        context.setCommitIndex(toIndex);
     }
 
     private void batchRecoveredLogEntry(ReplicatedLogEntry logEntry) {
@@ -270,11 +295,19 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
                 "Persistence Id =  " + persistenceId() +
                 " Last index in log={}, snapshotIndex={}, snapshotTerm={}, " +
                 "journal-size={}",
-            replicatedLog.lastIndex(), replicatedLog.snapshotIndex,
-            replicatedLog.snapshotTerm, replicatedLog.size());
+            replicatedLog.lastIndex(), replicatedLog.getSnapshotIndex(),
+            replicatedLog.getSnapshotTerm(), replicatedLog.size());
+
+        initializeBehavior();
+    }
 
+    protected void initializeBehavior(){
+        changeCurrentBehavior(new Follower(context));
+    }
+
+    protected void changeCurrentBehavior(RaftActorBehavior newBehavior){
         RaftActorBehavior oldBehavior = currentBehavior;
-        currentBehavior = new Follower(context);
+        currentBehavior = newBehavior;
         handleBehaviorChange(oldBehavior, currentBehavior);
     }
 
@@ -282,36 +315,40 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         if (message instanceof ApplyState){
             ApplyState applyState = (ApplyState) message;
 
+            long elapsedTime = (System.nanoTime() - applyState.getStartTime());
+            if(elapsedTime >= APPLY_STATE_DELAY_THRESHOLD_IN_NANOS){
+                LOG.warn("ApplyState took more time than expected. Elapsed Time = {} ms ApplyState = {}",
+                        TimeUnit.NANOSECONDS.toMillis(elapsedTime), applyState);
+            }
+
             if(LOG.isDebugEnabled()) {
-                LOG.debug("Applying state for log index {} data {}",
-                    applyState.getReplicatedLogEntry().getIndex(),
+                LOG.debug("{}: Applying state for log index {} data {}",
+                    persistenceId(), applyState.getReplicatedLogEntry().getIndex(),
                     applyState.getReplicatedLogEntry().getData());
             }
 
             applyState(applyState.getClientActor(), applyState.getIdentifier(),
                 applyState.getReplicatedLogEntry().getData());
 
-        } else if (message instanceof ApplyLogEntries){
-            ApplyLogEntries ale = (ApplyLogEntries) message;
+        } else if (message instanceof ApplyJournalEntries){
+            ApplyJournalEntries applyEntries = (ApplyJournalEntries) message;
             if(LOG.isDebugEnabled()) {
-                LOG.debug("Persisting ApplyLogEntries with index={}", ale.getToIndex());
+                LOG.debug("{}: Persisting ApplyLogEntries with index={}", persistenceId(), applyEntries.getToIndex());
             }
-            persistence().persist(new ApplyLogEntries(ale.getToIndex()), new Procedure<ApplyLogEntries>() {
-                @Override
-                public void apply(ApplyLogEntries param) throws Exception {
-                }
-            });
+
+            persistence().persist(applyEntries, APPLY_JOURNAL_ENTRIES_PERSIST_CALLBACK);
 
         } else if(message instanceof ApplySnapshot ) {
             Snapshot snapshot = ((ApplySnapshot) message).getSnapshot();
 
             if(LOG.isDebugEnabled()) {
-                LOG.debug("ApplySnapshot called on Follower Actor " +
-                        "snapshotIndex:{}, snapshotTerm:{}", snapshot.getLastAppliedIndex(),
+                LOG.debug("{}: ApplySnapshot called on Follower Actor " +
+                        "snapshotIndex:{}, snapshotTerm:{}", persistenceId(), snapshot.getLastAppliedIndex(),
                     snapshot.getLastAppliedTerm()
                 );
             }
-            applySnapshot(ByteString.copyFrom(snapshot.getState()));
+
+            applySnapshot(snapshot.getState());
 
             //clears the followers log, sets the snapshot index to ensure adjusted-index works
             replicatedLog = new ReplicatedLogImpl(snapshot);
@@ -326,7 +363,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
 
         } else if (message instanceof SaveSnapshotSuccess) {
             SaveSnapshotSuccess success = (SaveSnapshotSuccess) message;
-            LOG.info("SaveSnapshotSuccess received for snapshot");
+            LOG.info("{}: SaveSnapshotSuccess received for snapshot", persistenceId());
 
             long sequenceNumber = success.metadata().sequenceNr();
 
@@ -335,39 +372,30 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         } else if (message instanceof SaveSnapshotFailure) {
             SaveSnapshotFailure saveSnapshotFailure = (SaveSnapshotFailure) message;
 
-            LOG.info("saveSnapshotFailure.metadata():{}", saveSnapshotFailure.metadata().toString());
-            LOG.error(saveSnapshotFailure.cause(), "SaveSnapshotFailure received for snapshot Cause:");
+            LOG.error("{}: SaveSnapshotFailure received for snapshot Cause:",
+                    persistenceId(), saveSnapshotFailure.cause());
 
             context.getReplicatedLog().snapshotRollback();
 
-            LOG.info("Replicated Log rollbacked. Snapshot will be attempted in the next cycle." +
-                "snapshotIndex:{}, snapshotTerm:{}, log-size:{}",
+            LOG.info("{}: Replicated Log rollbacked. Snapshot will be attempted in the next cycle." +
+                "snapshotIndex:{}, snapshotTerm:{}, log-size:{}", persistenceId(),
                 context.getReplicatedLog().getSnapshotIndex(),
                 context.getReplicatedLog().getSnapshotTerm(),
                 context.getReplicatedLog().size());
 
         } else if (message instanceof CaptureSnapshot) {
-            LOG.info("CaptureSnapshot received by actor");
-            CaptureSnapshot cs = (CaptureSnapshot)message;
-            captureSnapshot = cs;
-            createSnapshot();
-
-        } else if (message instanceof CaptureSnapshotReply){
-            LOG.info("CaptureSnapshotReply received by actor");
-            CaptureSnapshotReply csr = (CaptureSnapshotReply) message;
-
-            ByteString stateInBytes = csr.getSnapshot();
-            LOG.info("CaptureSnapshotReply stateInBytes size:{}", stateInBytes.size());
-            handleCaptureSnapshotReply(stateInBytes);
+            LOG.debug("{}: CaptureSnapshot received by actor: {}", persistenceId(), message);
 
-        } else {
-            if (!(message instanceof AppendEntriesMessages.AppendEntries)
-                && !(message instanceof AppendEntriesReply) && !(message instanceof SendHeartBeat)) {
-                if(LOG.isDebugEnabled()) {
-                    LOG.debug("onReceiveCommand: message: {}", message.getClass());
-                }
+            if(captureSnapshot == null) {
+                captureSnapshot = (CaptureSnapshot)message;
+                createSnapshot();
             }
 
+        } else if (message instanceof CaptureSnapshotReply){
+            handleCaptureSnapshotReply(((CaptureSnapshotReply) message).getSnapshot());
+        } else if(message instanceof GetOnDemandRaftState) {
+            onGetOnDemandRaftStats();
+        } else {
             RaftActorBehavior oldBehavior = currentBehavior;
             currentBehavior = currentBehavior.handleMessage(getSender(), message);
 
@@ -375,19 +403,65 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         }
     }
 
+    private void onGetOnDemandRaftStats() {
+        // Debugging message to retrieve raft stats.
+
+        OnDemandRaftState.Builder builder = OnDemandRaftState.builder()
+                .commitIndex(context.getCommitIndex())
+                .currentTerm(context.getTermInformation().getCurrentTerm())
+                .inMemoryJournalDataSize(replicatedLog.dataSize())
+                .inMemoryJournalLogSize(replicatedLog.size())
+                .isSnapshotCaptureInitiated(context.isSnapshotCaptureInitiated())
+                .lastApplied(context.getLastApplied())
+                .lastIndex(replicatedLog.lastIndex())
+                .lastTerm(replicatedLog.lastTerm())
+                .leader(getLeaderId())
+                .raftState(currentBehavior.state().toString())
+                .replicatedToAllIndex(currentBehavior.getReplicatedToAllIndex())
+                .snapshotIndex(replicatedLog.getSnapshotIndex())
+                .snapshotTerm(replicatedLog.getSnapshotTerm())
+                .votedFor(context.getTermInformation().getVotedFor())
+                .peerAddresses(ImmutableMap.copyOf(context.getPeerAddresses()));
+
+        ReplicatedLogEntry lastLogEntry = getLastLogEntry();
+        if (lastLogEntry != null) {
+            builder.lastLogIndex(lastLogEntry.getIndex());
+            builder.lastLogTerm(lastLogEntry.getTerm());
+        }
+
+        if(currentBehavior instanceof AbstractLeader) {
+            AbstractLeader leader = (AbstractLeader)currentBehavior;
+            Collection<String> followerIds = leader.getFollowerIds();
+            List<FollowerInfo> followerInfoList = Lists.newArrayListWithCapacity(followerIds.size());
+            for(String id: followerIds) {
+                final FollowerLogInformation info = leader.getFollower(id);
+                followerInfoList.add(new FollowerInfo(id, info.getNextIndex(), info.getMatchIndex(),
+                        info.isFollowerActive(), DurationFormatUtils.formatDurationHMS(info.timeSinceLastActivity())));
+            }
+
+            builder.followerInfoList(followerInfoList);
+        }
+
+        sender().tell(builder.build(), self());
+
+    }
+
     private void handleBehaviorChange(RaftActorBehavior oldBehavior, RaftActorBehavior currentBehavior) {
         if (oldBehavior != currentBehavior){
             onStateChanged();
         }
-        if (oldBehavior != null) {
-            // it can happen that the state has not changed but the leader has changed.
-            onLeaderChanged(oldBehavior.getLeaderId(), currentBehavior.getLeaderId());
 
-            if (getRoleChangeNotifier().isPresent() && oldBehavior.state() != currentBehavior.state()) {
-                // we do not want to notify when the behavior/role is set for the first time (i.e follower)
-                getRoleChangeNotifier().get().tell(new RoleChanged(getId(), oldBehavior.state().name(),
-                    currentBehavior.state().name()), getSelf());
-            }
+        String oldBehaviorLeaderId = oldBehavior == null? null : oldBehavior.getLeaderId();
+        String oldBehaviorState = oldBehavior == null? null : oldBehavior.state().name();
+
+        // it can happen that the state has not changed but the leader has changed.
+        onLeaderChanged(oldBehaviorLeaderId, currentBehavior.getLeaderId());
+
+        if (getRoleChangeNotifier().isPresent() &&
+                (oldBehavior == null || (oldBehavior.state() != currentBehavior.state()))) {
+            getRoleChangeNotifier().get().tell(
+                    new RoleChanged(getId(), oldBehaviorState , currentBehavior.state().name()),
+                    getSelf());
         }
     }
 
@@ -407,7 +481,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
             context.getTermInformation().getCurrentTerm(), data);
 
         if(LOG.isDebugEnabled()) {
-            LOG.debug("Persist data {}", replicatedLogEntry);
+            LOG.debug("{}: Persist data {}", persistenceId(), replicatedLogEntry);
         }
 
         final RaftActorContext raftContext = getRaftActorContext();
@@ -424,17 +498,18 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
                             // Apply the state immediately
                             applyState(clientActor, identifier, data);
 
-                            // Send a ApplyLogEntries message so that we write the fact that we applied
+                            // Send a ApplyJournalEntries message so that we write the fact that we applied
                             // the state to durable storage
-                            self().tell(new ApplyLogEntries((int) replicatedLogEntry.getIndex()), self());
+                            self().tell(new ApplyJournalEntries(replicatedLogEntry.getIndex()), self());
 
                             // Check if the "real" snapshot capture has been initiated. If no then do the fake snapshot
-                            if(!hasSnapshotCaptureInitiated){
+                            if(!context.isSnapshotCaptureInitiated()){
                                 raftContext.getReplicatedLog().snapshotPreCommit(raftContext.getLastApplied(),
                                         raftContext.getTermInformation().getCurrentTerm());
                                 raftContext.getReplicatedLog().snapshotCommit();
                             } else {
-                                LOG.debug("Skipping fake snapshotting for {} because real snapshotting is in progress", getId());
+                                LOG.debug("{}: Skipping fake snapshotting for {} because real snapshotting is in progress",
+                                        persistenceId(), getId());
                             }
                         } else if (clientActor != null) {
                             // Send message for replication
@@ -510,6 +585,10 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         return context;
     }
 
+    protected void updateConfigParams(ConfigParams configParams) {
+        context.setConfigParams(configParams);
+    }
+
     /**
      * setPeerAddress sets the address of a known peer at a later time.
      * <p>
@@ -572,9 +651,9 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
     /**
      * This method is called during recovery to reconstruct the state of the actor.
      *
-     * @param snapshot A snapshot of the state of the actor
+     * @param snapshotBytes A snapshot of the state of the actor
      */
-    protected abstract void applyRecoverySnapshot(ByteString snapshot);
+    protected abstract void applyRecoverySnapshot(byte[] snapshotBytes);
 
     /**
      * This method is called during recovery at the end of a batch to apply the current batched
@@ -603,9 +682,9 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
      * operations when the derived actor is out of sync with it's peers
      * and the only way to bring it in sync is by applying a snapshot
      *
-     * @param snapshot A snapshot of the state of the actor
+     * @param snapshotBytes A snapshot of the state of the actor
      */
-    protected abstract void applySnapshot(ByteString snapshot);
+    protected abstract void applySnapshot(byte[] snapshotBytes);
 
     /**
      * This method will be called by the RaftActor when the state of the
@@ -645,44 +724,81 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
         }
         String peerAddress = context.getPeerAddress(leaderId);
         if(LOG.isDebugEnabled()) {
-            LOG.debug("getLeaderAddress leaderId = {} peerAddress = {}",
-                    leaderId, peerAddress);
+            LOG.debug("{}: getLeaderAddress leaderId = {} peerAddress = {}",
+                    persistenceId(), leaderId, peerAddress);
         }
 
         return peerAddress;
     }
 
-    private void handleCaptureSnapshotReply(ByteString stateInBytes) {
+    private void handleCaptureSnapshotReply(byte[] snapshotBytes) {
+        LOG.debug("{}: CaptureSnapshotReply received by actor: snapshot size {}", persistenceId(), snapshotBytes.length);
+
         // create a snapshot object from the state provided and save it
         // when snapshot is saved async, SaveSnapshotSuccess is raised.
 
-        Snapshot sn = Snapshot.create(stateInBytes.toByteArray(),
+        Snapshot sn = Snapshot.create(snapshotBytes,
             context.getReplicatedLog().getFrom(captureSnapshot.getLastAppliedIndex() + 1),
             captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
             captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm());
 
         persistence().saveSnapshot(sn);
 
-        LOG.info("Persisting of snapshot done:{}", sn.getLogMessage());
+        LOG.info("{}: Persisting of snapshot done:{}", persistenceId(), sn.getLogMessage());
+
+        long dataThreshold = getTotalMemory() *
+                getRaftActorContext().getConfigParams().getSnapshotDataThresholdPercentage() / 100;
+        if (context.getReplicatedLog().dataSize() > dataThreshold) {
 
-        //be greedy and remove entries from in-mem journal which are in the snapshot
-        // and update snapshotIndex and snapshotTerm without waiting for the success,
+            if(LOG.isDebugEnabled()) {
+                LOG.debug("{}: dataSize {} exceeds dataThreshold {} - doing snapshotPreCommit with index {}",
+                        persistenceId(), context.getReplicatedLog().dataSize(), dataThreshold,
+                        captureSnapshot.getLastAppliedIndex());
+            }
+
+            // if memory is less, clear the log based on lastApplied.
+            // this could/should only happen if one of the followers is down
+            // as normally we keep removing from the log when its replicated to all.
+            context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getLastAppliedIndex(),
+                    captureSnapshot.getLastAppliedTerm());
+
+            // Don't reset replicatedToAllIndex to -1 as this may prevent us from trimming the log after an
+            // install snapshot to a follower.
+            if(captureSnapshot.getReplicatedToAllIndex() >= 0) {
+                getCurrentBehavior().setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
+            }
+        } else if(captureSnapshot.getReplicatedToAllIndex() != -1){
+            // clear the log based on replicatedToAllIndex
+            context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getReplicatedToAllIndex(),
+                    captureSnapshot.getReplicatedToAllTerm());
+
+            getCurrentBehavior().setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
+        } else {
+            // The replicatedToAllIndex was not found in the log
+            // This means that replicatedToAllIndex never moved beyond -1 or that it is already in the snapshot.
+            // In this scenario we may need to save the snapshot to the akka persistence
+            // snapshot for recovery but we do not need to do the replicated log trimming.
+            context.getReplicatedLog().snapshotPreCommit(replicatedLog.getSnapshotIndex(),
+                    replicatedLog.getSnapshotTerm());
+        }
 
-        context.getReplicatedLog().snapshotPreCommit(
-            captureSnapshot.getLastAppliedIndex(),
-            captureSnapshot.getLastAppliedTerm());
 
-        LOG.info("Removed in-memory snapshotted entries, adjusted snaphsotIndex:{} " +
-            "and term:{}", captureSnapshot.getLastAppliedIndex(),
-            captureSnapshot.getLastAppliedTerm());
+        LOG.info("{}: Removed in-memory snapshotted entries, adjusted snaphsotIndex: {} " +
+            "and term: {}", persistenceId(), replicatedLog.getSnapshotIndex(),
+            replicatedLog.getSnapshotTerm());
 
         if (isLeader() && captureSnapshot.isInstallSnapshotInitiated()) {
             // this would be call straight to the leader and won't initiate in serialization
-            currentBehavior.handleMessage(getSelf(), new SendInstallSnapshot(stateInBytes));
+            currentBehavior.handleMessage(getSelf(), new SendInstallSnapshot(
+                    ByteString.copyFrom(snapshotBytes)));
         }
 
         captureSnapshot = null;
-        hasSnapshotCaptureInitiated = false;
+        context.setSnapshotCaptureInitiated(false);
+    }
+
+    protected long getTotalMemory() {
+        return Runtime.getRuntime().totalMemory();
     }
 
     protected boolean hasFollowers(){
@@ -713,13 +829,14 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
             // FIXME: Maybe this should be done after the command is saved
             journal.subList(adjustedIndex , journal.size()).clear();
 
-            persistence().persist(new DeleteEntries(adjustedIndex), new Procedure<DeleteEntries>(){
+            persistence().persist(new DeleteEntries(adjustedIndex), new Procedure<DeleteEntries>() {
 
-                @Override public void apply(DeleteEntries param)
-                    throws Exception {
+                @Override
+                public void apply(DeleteEntries param)
+                        throws Exception {
                     //FIXME : Doing nothing for now
                     dataSize = 0;
-                    for(ReplicatedLogEntry entry : journal){
+                    for (ReplicatedLogEntry entry : journal) {
                         dataSize += entry.size();
                     }
                 }
@@ -731,17 +848,12 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
             appendAndPersist(replicatedLogEntry, null);
         }
 
-        @Override
-        public int dataSize() {
-            return dataSize;
-        }
-
         public void appendAndPersist(
             final ReplicatedLogEntry replicatedLogEntry,
             final Procedure<ReplicatedLogEntry> callback)  {
 
             if(LOG.isDebugEnabled()) {
-                LOG.debug("Append log entry and persist {} ", replicatedLogEntry);
+                LOG.debug("{}: Append log entry and persist {} ", persistenceId(), replicatedLogEntry);
             }
 
             // FIXME : By adding the replicated log entry to the in-memory journal we are not truly ensuring durability of the logs
@@ -762,7 +874,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
                         long dataSizeForCheck = dataSize;
 
                         dataSizeSinceLastSnapshot += logEntrySize;
-                        long journalSize = lastIndex()+1;
+                        long journalSize = lastIndex() + 1;
 
                         if(!hasFollowers()) {
                             // When we do not have followers we do not maintain an in-memory log
@@ -779,17 +891,19 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
                             dataSizeForCheck = dataSizeSinceLastSnapshot / DATA_SIZE_DIVIDER;
                         }
 
-                        long dataThreshold = Runtime.getRuntime().totalMemory() *
+                        long dataThreshold = getTotalMemory() *
                                 getRaftActorContext().getConfigParams().getSnapshotDataThresholdPercentage() / 100;
 
                         // when a snaphsot is being taken, captureSnapshot != null
-                        if (hasSnapshotCaptureInitiated == false &&
+                        if (!context.isSnapshotCaptureInitiated() &&
                                 ( journalSize % context.getConfigParams().getSnapshotBatchCount() == 0 ||
                                         dataSizeForCheck > dataThreshold)) {
 
                             dataSizeSinceLastSnapshot = 0;
 
-                            LOG.info("Initiating Snapshot Capture..");
+                            LOG.info("{}: Initiating Snapshot Capture, journalSize = {}, dataSizeForCheck = {}," +
+                                " dataThreshold = {}", persistenceId(), journalSize, dataSizeForCheck, dataThreshold);
+
                             long lastAppliedIndex = -1;
                             long lastAppliedTerm = -1;
 
@@ -803,20 +917,25 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
                             }
 
                             if(LOG.isDebugEnabled()) {
-                                LOG.debug("Snapshot Capture logSize: {}", journal.size());
-                                LOG.debug("Snapshot Capture lastApplied:{} ",
-                                    context.getLastApplied());
-                                LOG.debug("Snapshot Capture lastAppliedIndex:{}", lastAppliedIndex);
-                                LOG.debug("Snapshot Capture lastAppliedTerm:{}", lastAppliedTerm);
+                                LOG.debug("{}: Snapshot Capture logSize: {}", persistenceId(), journal.size());
+                                LOG.debug("{}: Snapshot Capture lastApplied:{} ",
+                                        persistenceId(), context.getLastApplied());
+                                LOG.debug("{}: Snapshot Capture lastAppliedIndex:{}", persistenceId(),
+                                        lastAppliedIndex);
+                                LOG.debug("{}: Snapshot Capture lastAppliedTerm:{}", persistenceId(),
+                                        lastAppliedTerm);
                             }
 
                             // send a CaptureSnapshot to self to make the expensive operation async.
-                            getSelf().tell(new CaptureSnapshot(
-                                lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm),
+                            long replicatedToAllIndex = getCurrentBehavior().getReplicatedToAllIndex();
+                            ReplicatedLogEntry replicatedToAllEntry = context.getReplicatedLog().get(replicatedToAllIndex);
+                            getSelf().tell(new CaptureSnapshot(lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm,
+                                (replicatedToAllEntry != null ? replicatedToAllEntry.getIndex() : -1),
+                                (replicatedToAllEntry != null ? replicatedToAllEntry.getTerm() : -1)),
                                 null);
-                            hasSnapshotCaptureInitiated = true;
+                            context.setSnapshotCaptureInitiated(true);
                         }
-                        if(callback != null){
+                        if (callback != null){
                             callback.apply(replicatedLogEntry);
                         }
                     }
@@ -859,7 +978,7 @@ public abstract class RaftActor extends AbstractUntypedPersistentActor {
 
         @Override public void update(long currentTerm, String votedFor) {
             if(LOG.isDebugEnabled()) {
-                LOG.debug("Set currentTerm={}, votedFor={}", currentTerm, votedFor);
+                LOG.debug("{}: Set currentTerm={}, votedFor={}", persistenceId(), currentTerm, votedFor);
             }
             this.currentTerm = currentTerm;
             this.votedFor = votedFor;