diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/FileStore.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/FileStore.cs
index b31ba3c..4c0cddf 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/FileStore.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/FileStore.cs
@@ -18,6 +18,7 @@ using System.Security.Cryptography;
 using System.Text;
 using System.Text.Json;
 using System.Threading.Channels;
+using ZB.MOM.NatsNet.Server.Internal;
 using ZB.MOM.NatsNet.Server.Internal.DataStructures;
 
 namespace ZB.MOM.NatsNet.Server;
@@ -68,6 +69,8 @@ public sealed class JetStreamFileStore : IStreamStore, IDisposable
 
     // Per-subject index map
     private SubjectTree<Psi>? _psim;
+    private HashWheel? _ttls;
+    private MsgScheduling? _scheduling;
 
     // Total subject-list length (sum of subject-string lengths)
     private int _tsl;
@@ -117,6 +120,12 @@ public sealed class JetStreamFileStore : IStreamStore, IDisposable
     private const int ConsumerHeaderLength = 2;
     private const int MaxVarIntLength = 10;
     private const long NanosecondsPerSecond = 1_000_000_000L;
+    private const byte FullStateMagic = 11;
+    private const byte FullStateMinVersion = 1;
+    private const byte FullStateVersion = 3;
+    private const int FullStateHeaderLength = 2;
+    private const int FullStateMinimumLength = 32;
+    private const int FullStateChecksumLength = 8;
 
     static JetStreamFileStore()
     {
@@ -1024,6 +1033,685 @@ public sealed class JetStreamFileStore : IStreamStore, IDisposable
         return mb;
     }
 
+    internal void Warn(string format, params object?[] args)
+    {
+        if (_fcfg.Server is not NatsServer server)
+            return;
+
+        server.Warnf("Filestore [{0}] " + format, BuildLogArgs(args));
+    }
+
+    internal void Debug(string format, params object?[] args)
+    {
+        if (_fcfg.Server is not NatsServer server)
+            return;
+
+        server.Debugf("Filestore [{0}] " + format, BuildLogArgs(args));
+    }
+
+    internal Exception? RecoverFullState()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            RecoverPartialPurge();
+
+            var fn = Path.Combine(_fcfg.StoreDir, FileStoreDefaults.MsgDir, FileStoreDefaults.StreamStateFile);
+            byte[] raw;
+            try
+            {
+                raw = File.ReadAllBytes(fn);
+            }
+            catch (FileNotFoundException ex)
+            {
+                return ex;
+            }
+            catch (DirectoryNotFoundException ex)
+            {
+                return ex;
+            }
+            catch (Exception ex)
+            {
+                Warn("Could not read stream state file: {0}", ex);
+                return ex;
+            }
+
+            if (raw.Length < FullStateMinimumLength)
+            {
+                TryDeleteFile(fn);
+                Warn("Stream state too short ({0} bytes)", raw.Length);
+                return new InvalidDataException("corrupt state");
+            }
+
+            if (!TryValidateFullStateChecksum(raw, out var buf))
+            {
+                TryDeleteFile(fn);
+                Warn("Stream state checksum did not match");
+                return new InvalidDataException("corrupt state");
+            }
+
+            if (_prf != null && _aek != null)
+            {
+                var ns = _aek.NonceSize;
+                if (buf.Length <= ns)
+                {
+                    Warn("Stream state error reading encryption key: malformed ciphertext");
+                    return new InvalidDataException("corrupt state");
+                }
+
+                try
+                {
+                    buf = _aek.Open(buf.AsSpan(0, ns), buf.AsSpan(ns));
+                }
+                catch (Exception ex)
+                {
+                    Warn("Stream state error reading encryption key: {0}", ex);
+                    return ex;
+                }
+            }
+
+            if (buf.Length < FullStateHeaderLength)
+            {
+                TryDeleteFile(fn);
+                Warn("Stream state missing header");
+                return new InvalidDataException("corrupt state");
+            }
+
+            var version = buf[1];
+            if (buf[0] != FullStateMagic || version < FullStateMinVersion || version > FullStateVersion)
+            {
+                TryDeleteFile(fn);
+                Warn("Stream state magic and version mismatch");
+                return new InvalidDataException("corrupt state");
+            }
+
+            var bi = FullStateHeaderLength;
+            if (!TryReadUVarInt(buf, ref bi, out var msgs) ||
+                !TryReadUVarInt(buf, ref bi, out var bytes) ||
+                !TryReadUVarInt(buf, ref bi, out var firstSeq) ||
+                !TryReadVarInt(buf, ref bi, out var baseTime) ||
+                !TryReadUVarInt(buf, ref bi, out var lastSeq) ||
+                !TryReadVarInt(buf, ref bi, out var lastTs))
+            {
+                TryDeleteFile(fn);
+                Warn("Stream state could not decode stream summary");
+                return new InvalidDataException("corrupt state");
+            }
+
+            var recoveredState = new StreamState
+            {
+                Msgs = msgs,
+                Bytes = bytes,
+                FirstSeq = firstSeq,
+                LastSeq = lastSeq,
+                FirstTime = baseTime == 0 ? default : FromUnixNanosUtc(baseTime),
+                LastTime = lastTs == 0 ? default : FromUnixNanosUtc(lastTs),
+            };
+
+            _psim ??= new SubjectTree<Psi>();
+            _psim.Reset();
+            _tsl = 0;
+
+            if (!TryReadUVarInt(buf, ref bi, out var numSubjects))
+                return CorruptStateWithDelete(fn, "Stream state missing subject metadata");
+
+            for (var i = 0UL; i < numSubjects; i++)
+            {
+                if (!TryReadUVarInt(buf, ref bi, out var subjectLength))
+                    return CorruptStateWithDelete(fn, "Stream state subject length decode failed");
+
+                if (subjectLength == 0)
+                    continue;
+
+                if (bi < 0 || bi + (int)subjectLength > buf.Length)
+                    return CorruptStateWithDelete(fn, $"Stream state bad subject len ({subjectLength})");
+
+                var subject = Encoding.Latin1.GetString(buf, bi, (int)subjectLength);
+                if (!SubscriptionIndex.IsValidLiteralSubject(subject))
+                    return CorruptStateWithDelete(fn, "Stream state corrupt subject detected");
+
+                bi += (int)subjectLength;
+                if (!TryReadUVarInt(buf, ref bi, out var total) || !TryReadUVarInt(buf, ref bi, out var fblk))
+                    return CorruptStateWithDelete(fn, "Stream state could not decode subject index");
+
+                ulong lblk = fblk;
+                if (total > 1)
+                {
+                    if (!TryReadUVarInt(buf, ref bi, out lblk))
+                        return CorruptStateWithDelete(fn, "Stream state could not decode subject last block");
+                }
+
+                _psim.Insert(Encoding.Latin1.GetBytes(subject), new Psi
+                {
+                    Total = total,
+                    Fblk = (uint)fblk,
+                    Lblk = (uint)lblk,
+                });
+                _tsl += (int)subjectLength;
+            }
+
+            if (!TryReadUVarInt(buf, ref bi, out var numBlocks))
+                return CorruptStateWithDelete(fn, "Stream state could not decode block count");
+
+            var parsedBlocks = new List<MessageBlock>((int)numBlocks);
+            var parsedMap = new Dictionary<uint, MessageBlock>((int)numBlocks);
+            var mstate = new StreamState();
+            var lastBlockIndex = numBlocks > 0 ? numBlocks - 1 : 0;
+
+            for (var i = 0UL; i < numBlocks; i++)
+            {
+                if (!TryReadUVarInt(buf, ref bi, out var idx) ||
+                    !TryReadUVarInt(buf, ref bi, out var nbytes) ||
+                    !TryReadUVarInt(buf, ref bi, out var fseq) ||
+                    !TryReadVarInt(buf, ref bi, out var fts) ||
+                    !TryReadUVarInt(buf, ref bi, out var lseq) ||
+                    !TryReadVarInt(buf, ref bi, out var lts) ||
+                    !TryReadUVarInt(buf, ref bi, out var numDeleted))
+                {
+                    return CorruptStateWithDelete(fn, "Stream state block decode failed");
+                }
+
+                ulong ttls = 0;
+                if (version >= 2)
+                {
+                    if (!TryReadUVarInt(buf, ref bi, out ttls))
+                        return CorruptStateWithDelete(fn, "Stream state TTL metadata decode failed");
+                }
+
+                ulong schedules = 0;
+                if (version >= 3)
+                {
+                    if (!TryReadUVarInt(buf, ref bi, out schedules))
+                        return CorruptStateWithDelete(fn, "Stream state schedule metadata decode failed");
+                }
+
+                var mb = InitMsgBlock((uint)idx);
+                mb.First = new MsgId { Seq = fseq, Ts = fts + baseTime };
+                mb.Last = new MsgId { Seq = lseq, Ts = lts + baseTime };
+                mb.Bytes = nbytes;
+                mb.Msgs = lseq >= fseq ? (lseq - fseq + 1) : 0;
+                mb.Ttls = ttls;
+                mb.Schedules = schedules;
+                mb.Closed = true;
+
+                if (numDeleted > 0)
+                {
+                    try
+                    {
+                        var (dmap, consumed) = SequenceSet.Decode(buf.AsSpan(bi));
+                        if (consumed <= 0)
+                            return CorruptStateWithDelete(fn, "Stream state error decoding deleted map");
+
+                        mb.Dmap = dmap;
+                        mb.Msgs = mb.Msgs > numDeleted ? (mb.Msgs - numDeleted) : 0;
+                        bi += consumed;
+                    }
+                    catch (Exception ex)
+                    {
+                        Warn("Stream state error decoding deleted map: {0}", ex);
+                        return CorruptStateWithDelete(fn, "Stream state error decoding deleted map");
+                    }
+                }
+
+                if (mb.Msgs > 0 || i == lastBlockIndex)
+                {
+                    parsedBlocks.Add(mb);
+                    parsedMap[mb.Index] = mb;
+                    UpdateTrackingState(mstate, mb);
+                }
+                else
+                {
+                    _dirty++;
+                }
+            }
+
+            if (!TryReadUVarInt(buf, ref bi, out var blkIndex))
+                return CorruptStateWithDelete(fn, "Stream state has no block index");
+
+            if (bi < 0 || bi + FullStateChecksumLength > buf.Length)
+                return CorruptStateWithDelete(fn, "Stream state has no checksum present");
+
+            var lchk = buf.AsSpan(bi, FullStateChecksumLength).ToArray();
+
+            _state = recoveredState;
+            _blks = parsedBlocks;
+            _bim = parsedMap;
+            _lmb = _blks.Count > 0 ? _blks[^1] : null;
+
+            if (_lmb == null || _lmb.Index != (uint)blkIndex)
+                return CorruptStateWithDelete(fn, "Stream state block does not exist or index mismatch");
+
+            if (!File.Exists(_lmb.Mfn))
+            {
+                Warn("Stream state detected prior state, could not locate msg block {0}", blkIndex);
+                return new InvalidOperationException("prior stream state detected");
+            }
+
+            if (!LastChecksumMatches(_lmb, lchk))
+            {
+                Warn("Stream state outdated, last block has additional entries, will rebuild");
+                return new InvalidOperationException("prior stream state detected");
+            }
+
+            var mdir = Path.Combine(_fcfg.StoreDir, FileStoreDefaults.MsgDir);
+            if (Directory.Exists(mdir))
+            {
+                foreach (var path in Directory.EnumerateFiles(mdir, "*" + FileStoreDefaults.BlkSuffix, SearchOption.TopDirectoryOnly))
+                {
+                    if (!TryParseBlockIndex(Path.GetFileName(path), out var index))
+                        continue;
+
+                    if (index > blkIndex)
+                    {
+                        Warn("Stream state outdated, found extra blocks, will rebuild");
+                        return new InvalidOperationException("prior stream state detected");
+                    }
+
+                    if (index <= uint.MaxValue && _bim.TryGetValue((uint)index, out var mb))
+                        mb.Closed = false;
+                }
+            }
+
+            var rebuildRequired = false;
+            foreach (var mb in _blks)
+            {
+                if (!mb.Closed)
+                    continue;
+
+                rebuildRequired = true;
+                Warn("Stream state detected prior state, could not locate msg block {0}", mb.Index);
+            }
+
+            if (rebuildRequired)
+                return new InvalidOperationException("prior stream state detected");
+
+            if (!TrackingStatesEqual(_state, mstate))
+                return CorruptStateWithDelete(fn, "Stream state encountered internal inconsistency on recover");
+
+            return null;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    private object?[] BuildLogArgs(object?[] args)
+    {
+        if (args.Length == 0)
+            return [_cfg.Config.Name];
+
+        var formatted = new object?[args.Length + 1];
+        formatted[0] = _cfg.Config.Name;
+        Array.Copy(args, 0, formatted, 1, args.Length);
+        return formatted;
+    }
+
+    private Exception CorruptStateWithDelete(string fileName, string message)
+    {
+        TryDeleteFile(fileName);
+        Warn("{0}", message);
+        return new InvalidDataException("corrupt state");
+    }
+
+    private static void TryDeleteFile(string fileName)
+    {
+        try
+        {
+            if (File.Exists(fileName))
+                File.Delete(fileName);
+        }
+        catch
+        {
+            // Best effort to drop unusable snapshots.
+        }
+    }
+
+    private bool TryValidateFullStateChecksum(byte[] raw, out byte[] payload)
+    {
+        payload = Array.Empty<byte>();
+        if (raw.Length <= FullStateChecksumLength)
+            return false;
+
+        var contentLength = raw.Length - FullStateChecksumLength;
+        payload = raw[..contentLength];
+        var checksum = raw.AsSpan(contentLength, FullStateChecksumLength);
+
+        var key = SHA256.HashData(Encoding.UTF8.GetBytes(_cfg.Config.Name));
+        using var hmac = new HMACSHA256(key);
+        var digest = hmac.ComputeHash(payload);
+        return checksum.SequenceEqual(digest.AsSpan(0, FullStateChecksumLength));
+    }
+
+    private bool LastChecksumMatches(MessageBlock mb, byte[] expected)
+    {
+        try
+        {
+            using var fs = new FileStream(mb.Mfn, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+            if (fs.Length < FileStoreDefaults.RecordHashSize)
+                return expected.AsSpan().SequenceEqual(new byte[FileStoreDefaults.RecordHashSize]);
+
+            var lchk = new byte[FileStoreDefaults.RecordHashSize];
+            fs.Seek(-FileStoreDefaults.RecordHashSize, SeekOrigin.End);
+            fs.ReadExactly(lchk, 0, lchk.Length);
+            return expected.AsSpan().SequenceEqual(lchk);
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static bool TryParseBlockIndex(string fileName, out ulong index)
+    {
+        index = 0;
+        if (!fileName.EndsWith(FileStoreDefaults.BlkSuffix, StringComparison.Ordinal))
+            return false;
+
+        var stem = Path.GetFileNameWithoutExtension(fileName);
+        return ulong.TryParse(stem, out index);
+    }
+
+    private void RecoverPartialPurge()
+    {
+        var storeDir = _fcfg.StoreDir;
+        var msgDir = Path.Combine(storeDir, FileStoreDefaults.MsgDir);
+        var purgeDir = Path.Combine(storeDir, FileStoreDefaults.PurgeDir);
+        var newMsgDir = Path.Combine(storeDir, FileStoreDefaults.NewMsgDir);
+
+        if (!Directory.Exists(msgDir))
+        {
+            if (Directory.Exists(newMsgDir))
+            {
+                Directory.Move(newMsgDir, msgDir);
+            }
+            else if (Directory.Exists(purgeDir))
+            {
+                Directory.Move(purgeDir, msgDir);
+            }
+
+            return;
+        }
+
+        if (Directory.Exists(newMsgDir))
+            Directory.Delete(newMsgDir, recursive: true);
+        if (Directory.Exists(purgeDir))
+            Directory.Delete(purgeDir, recursive: true);
+    }
+
+    private void ResetAgeChk(long delta)
+    {
+        if (_ageChkRun)
+            return;
+
+        long next = long.MaxValue;
+        if (_ttls != null)
+            next = _ttls.GetNextExpiration(next);
+
+        if (_cfg.Config.MaxAge <= TimeSpan.Zero && next == long.MaxValue)
+        {
+            CancelAgeChk();
+            return;
+        }
+
+        var fireIn = _cfg.Config.MaxAge;
+        if (delta == 0 && _state.Msgs > 0)
+        {
+            var until = TimeSpan.FromSeconds(2);
+            if (fireIn == TimeSpan.Zero || until < fireIn)
+                fireIn = until;
+        }
+
+        if (next < long.MaxValue)
+        {
+            var nextTicks = DateTime.UnixEpoch.Ticks + next / 100L;
+            var nextUtc = new DateTime(Math.Max(nextTicks, DateTime.UnixEpoch.Ticks), DateTimeKind.Utc);
+            var until = nextUtc - DateTime.UtcNow;
+            if (fireIn == TimeSpan.Zero || until < fireIn)
+                fireIn = until;
+        }
+
+        if (delta > 0)
+        {
+            var deltaDur = TimeSpan.FromTicks(delta / 100L);
+            if (fireIn == TimeSpan.Zero || deltaDur < fireIn)
+                fireIn = deltaDur;
+        }
+
+        if (fireIn < TimeSpan.FromMilliseconds(250))
+            fireIn = TimeSpan.FromMilliseconds(250);
+
+        var expires = DateTime.UtcNow.Ticks + fireIn.Ticks;
+        if (_ageChkTime > 0 && expires > _ageChkTime)
+            return;
+
+        _ageChkTime = expires;
+        if (_ageChk != null)
+            _ageChk.Change(fireIn, Timeout.InfiniteTimeSpan);
+        else
+            _ageChk = new Timer(_ => { }, null, fireIn, Timeout.InfiniteTimeSpan);
+    }
+
+    private void CancelAgeChk()
+    {
+        _ageChk?.Dispose();
+        _ageChk = null;
+        _ageChkTime = 0;
+    }
+
+    private void RunMsgScheduling()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _scheduling?.ResetTimer();
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal Exception? RecoverTTLState()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            var fn = Path.Combine(_fcfg.StoreDir, FileStoreDefaults.MsgDir, FileStoreDefaults.TtlStreamStateFile);
+            byte[]? buf = null;
+
+            try
+            {
+                if (File.Exists(fn))
+                    buf = File.ReadAllBytes(fn);
+            }
+            catch (Exception ex)
+            {
+                return ex;
+            }
+
+            _ttls = HashWheel.NewHashWheel();
+
+            ulong ttlSeq = 0;
+            if (buf != null)
+            {
+                try
+                {
+                    ttlSeq = _ttls.Decode(buf);
+                }
+                catch (Exception ex)
+                {
+                    Warn("Error decoding TTL state: {0}", ex);
+                    TryDeleteFile(fn);
+                }
+            }
+
+            if (ttlSeq < _state.FirstSeq)
+                ttlSeq = _state.FirstSeq;
+
+            try
+            {
+                if (_state.Msgs > 0 && ttlSeq <= _state.LastSeq)
+                {
+                    Warn("TTL state is outdated; attempting to recover using linear scan (seq {0} to {1})", ttlSeq, _state.LastSeq);
+                    foreach (var mb in _blks)
+                    {
+                        mb.Mu.EnterReadLock();
+                        try
+                        {
+                            if (mb.Ttls == 0 || mb.Last.Seq < ttlSeq)
+                                continue;
+
+                            var start = Math.Max(ttlSeq, mb.First.Seq);
+                            var end = mb.Last.Seq;
+                            for (var seq = start; seq <= end; seq++)
+                            {
+                                StoreMsg? sm = null;
+                                try
+                                {
+                                    sm = LoadMsg(seq, null);
+                                }
+                                catch (Exception ex)
+                                {
+                                    Warn("Error loading msg seq {0} for recovering TTL: {1}", seq, ex);
+                                }
+
+                                if (sm?.Hdr is not { Length: > 0 })
+                                {
+                                    if (seq == ulong.MaxValue)
+                                        break;
+                                    continue;
+                                }
+
+                                var (ttl, _) = JetStreamHeaderHelpers.GetMessageTtl(sm.Hdr);
+                                if (ttl > 0)
+                                {
+                                    var expires = sm.Ts + (ttl * NanosecondsPerSecond);
+                                    _ttls.Add(seq, expires);
+                                }
+
+                                if (seq == ulong.MaxValue)
+                                    break;
+                            }
+                        }
+                        finally
+                        {
+                            mb.Mu.ExitReadLock();
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                ResetAgeChk(0);
+            }
+
+            return null;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal Exception? RecoverMsgSchedulingState()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            var fn = Path.Combine(_fcfg.StoreDir, FileStoreDefaults.MsgDir, FileStoreDefaults.MsgSchedulingStreamStateFile);
+            byte[]? buf = null;
+
+            try
+            {
+                if (File.Exists(fn))
+                    buf = File.ReadAllBytes(fn);
+            }
+            catch (Exception ex)
+            {
+                return ex;
+            }
+
+            _scheduling = new MsgScheduling(RunMsgScheduling);
+
+            ulong schedSeq = 0;
+            if (buf != null)
+            {
+                var (decodedSeq, err) = _scheduling.Decode(buf);
+                schedSeq = decodedSeq;
+                if (err != null)
+                {
+                    Warn("Error decoding message scheduling state: {0}", err);
+                    TryDeleteFile(fn);
+                    schedSeq = 0;
+                }
+            }
+
+            if (schedSeq < _state.FirstSeq)
+                schedSeq = _state.FirstSeq;
+
+            try
+            {
+                if (_state.Msgs > 0 && schedSeq <= _state.LastSeq)
+                {
+                    Warn("Message scheduling state is outdated; attempting to recover using linear scan (seq {0} to {1})", schedSeq, _state.LastSeq);
+                    foreach (var mb in _blks)
+                    {
+                        mb.Mu.EnterReadLock();
+                        try
+                        {
+                            if (mb.Schedules == 0 || mb.Last.Seq < schedSeq)
+                                continue;
+
+                            var start = Math.Max(schedSeq, mb.First.Seq);
+                            var end = mb.Last.Seq;
+                            for (var seq = start; seq <= end; seq++)
+                            {
+                                StoreMsg? sm = null;
+                                try
+                                {
+                                    sm = LoadMsg(seq, null);
+                                }
+                                catch (Exception ex)
+                                {
+                                    Warn("Error loading msg seq {0} for recovering message schedules: {1}", seq, ex);
+                                }
+
+                                if (sm?.Hdr is not { Length: > 0 })
+                                {
+                                    if (seq == ulong.MaxValue)
+                                        break;
+                                    continue;
+                                }
+
+                                var (schedule, ok) = JetStreamHeaderHelpers.NextMessageSchedule(sm.Hdr, sm.Ts);
+                                if (ok && schedule != default)
+                                    _scheduling.Init(seq, sm.Subject, schedule.Ticks * 100L);
+
+                                if (seq == ulong.MaxValue)
+                                    break;
+                            }
+                        }
+                        finally
+                        {
+                            mb.Mu.ExitReadLock();
+                        }
+                    }
+                }
+            }
+            finally
+            {
+                _scheduling.ResetTimer();
+            }
+
+            return null;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
     private static void EnsureStoreDirectoryWritable(string storeDir)
     {
         if (string.IsNullOrWhiteSpace(storeDir))
diff --git a/porting.db b/porting.db
index 448065f..49f5c77 100644
Binary files a/porting.db and b/porting.db differ