diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/DbHealthProbeActor.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/DbHealthProbeActor.cs
new file mode 100644
index 0000000..2d9c17c
--- /dev/null
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/DbHealthProbeActor.cs
@@ -0,0 +1,58 @@
+using Akka.Actor;
+using Akka.Event;
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Health;
+
+/// <summary>
+/// Single-flight cached health probe against the ConfigDb. Reads cached state via
+/// <c>Ask&lt;DbHealthStatus&gt;</c>; a single SELECT 1 runs at most every <c>RefreshInterval</c>.
+/// Consumed by both the host's <c>/health/ready</c> endpoint (Task 54) and
+/// <c>RedundancyStateActor</c>'s stale calc.
+/// </summary>
+public sealed class DbHealthProbeActor : ReceiveActor, IWithTimers
+{
+    public static readonly TimeSpan RefreshInterval = TimeSpan.FromSeconds(5);
+
+    public sealed class GetStatus { public static readonly GetStatus Instance = new(); private GetStatus() { } }
+    public sealed record DbHealthStatus(bool Reachable, DateTime AsOfUtc, string? LastError);
+    public sealed class Tick { public static readonly Tick Instance = new(); private Tick() { } }
+
+    private readonly IDbContextFactory<OtOpcUaConfigDbContext> _dbFactory;
+    private readonly ILoggingAdapter _log = Context.GetLogger();
+    private DbHealthStatus _last = new(false, DateTime.MinValue, "not probed yet");
+
+    public ITimerScheduler Timers { get; set; } = null!;
+
+    public static Props Props(IDbContextFactory<OtOpcUaConfigDbContext> dbFactory) =>
+        Akka.Actor.Props.Create(() => new DbHealthProbeActor(dbFactory));
+
+    public DbHealthProbeActor(IDbContextFactory<OtOpcUaConfigDbContext> dbFactory)
+    {
+        _dbFactory = dbFactory;
+        Receive<GetStatus>(_ => Sender.Tell(_last));
+        Receive<Tick>(_ => RunProbe());
+    }
+
+    protected override void PreStart()
+    {
+        RunProbe();
+        Timers.StartPeriodicTimer("probe", Tick.Instance, RefreshInterval);
+    }
+
+    private void RunProbe()
+    {
+        try
+        {
+            using var db = _dbFactory.CreateDbContext();
+            _ = db.Deployments.AsNoTracking().Take(1).ToList();
+            _last = new DbHealthStatus(true, DateTime.UtcNow, null);
+        }
+        catch (Exception ex)
+        {
+            _last = new DbHealthStatus(false, DateTime.UtcNow, ex.Message);
+            _log.Warning(ex, "DbHealthProbe: probe failed");
+        }
+    }
+}
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/PeerOpcUaProbeActor.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/PeerOpcUaProbeActor.cs
new file mode 100644
index 0000000..7e8c157
--- /dev/null
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Health/PeerOpcUaProbeActor.cs
@@ -0,0 +1,54 @@
+using Akka.Actor;
+using Akka.Cluster.Tools.PublishSubscribe;
+using Akka.Event;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Health;
+
+/// <summary>
+/// Periodically pings a peer node's OPC UA endpoint (<c>opc.tcp://peer:4840</c>) and publishes
+/// the result on the cluster's redundancy-state input topic so the admin <c>RedundancyStateActor</c>
+/// can react. Real OPC UA probe call is staged for follow-up F12.
+/// </summary>
+public sealed class PeerOpcUaProbeActor : ReceiveActor, IWithTimers
+{
+    // Owned by ControlPlane.Redundancy.RedundancyStateActor; duplicated here to avoid a
+    // Runtime → ControlPlane project reference. Keep both literals in lock-step.
+    public const string RedundancyStateTopic = "redundancy-state";
+
+    public static readonly TimeSpan DefaultProbeInterval = TimeSpan.FromSeconds(10);
+
+    public sealed record OpcUaProbeResult(NodeId NodeId, bool Ok);
+    public sealed class Tick { public static readonly Tick Instance = new(); private Tick() { } }
+
+    private readonly NodeId _peer;
+    private readonly TimeSpan _interval;
+    private readonly Action<object>? _broadcastOverride;
+    private readonly ILoggingAdapter _log = Context.GetLogger();
+
+    public ITimerScheduler Timers { get; set; } = null!;
+
+    public static Props Props(NodeId peer, TimeSpan? interval = null, Action<object>? broadcast = null) =>
+        Akka.Actor.Props.Create(() => new PeerOpcUaProbeActor(peer, interval ?? DefaultProbeInterval, broadcast));
+
+    public PeerOpcUaProbeActor(NodeId peer, TimeSpan interval, Action<object>? broadcastOverride)
+    {
+        _peer = peer;
+        _interval = interval;
+        _broadcastOverride = broadcastOverride;
+
+        Receive<Tick>(_ => RunProbe());
+    }
+
+    protected override void PreStart() =>
+        Timers.StartPeriodicTimer("probe", Tick.Instance, _interval);
+
+    private void RunProbe()
+    {
+        // F12: actual opc.tcp ping. Assume Ok=true until the probe is wired.
+        var msg = new OpcUaProbeResult(_peer, Ok: true);
+        if (_broadcastOverride is not null) _broadcastOverride(msg);
+        else DistributedPubSub.Get(Context.System).Mediator.Tell(new Publish(RedundancyStateTopic, msg));
+        _log.Debug("PeerOpcUaProbe: pinged {Peer} (probe staged for F12)", _peer);
+    }
+}
diff --git a/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/HistorianAdapterActor.cs b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/HistorianAdapterActor.cs
new file mode 100644
index 0000000..7f5315d
--- /dev/null
+++ b/src/Server/ZB.MOM.WW.OtOpcUa.Runtime/Historian/HistorianAdapterActor.cs
@@ -0,0 +1,32 @@
+using Akka.Actor;
+using Akka.Event;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+
+/// <summary>
+/// Wraps the named-pipe IPC to the Wonderware historian sidecar with a store-and-forward
+/// SQLite buffer for pipe outages. Engine wiring (named-pipe client + <c>SqliteStoreAndForwardSink</c>)
+/// is staged for follow-up F11.
+/// </summary>
+public sealed class HistorianAdapterActor : ReceiveActor
+{
+    public sealed record HistoryRow(string Source, string AttributeId, object? Value, DateTime TimestampUtc);
+
+    private readonly ILoggingAdapter _log = Context.GetLogger();
+    private int _buffered;
+
+    public int BufferedCount => _buffered;
+
+    public static Props Props() => Akka.Actor.Props.Create(() => new HistorianAdapterActor());
+
+    public HistorianAdapterActor()
+    {
+        Receive<HistoryRow>(row =>
+        {
+            // F11: dispatch to named-pipe sink; on disconnect → buffer in SQLite.
+            Interlocked.Increment(ref _buffered);
+            _log.Debug("Historian: buffered row for {Source}/{Attr} (sink wiring staged for F11)",
+                row.Source, row.AttributeId);
+        });
+    }
+}
diff --git a/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Health/HealthProbeActorTests.cs b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Health/HealthProbeActorTests.cs
new file mode 100644
index 0000000..fc7c910
--- /dev/null
+++ b/tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Health/HealthProbeActorTests.cs
@@ -0,0 +1,50 @@
+using Akka.Actor;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Commons.Types;
+using ZB.MOM.WW.OtOpcUa.Runtime.Health;
+using ZB.MOM.WW.OtOpcUa.Runtime.Historian;
+using ZB.MOM.WW.OtOpcUa.Runtime.Tests.Harness;
+
+namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests.Health;
+
+public sealed class HealthProbeActorTests : RuntimeActorTestBase
+{
+    [Fact]
+    public async Task DbHealthProbeActor_returns_reachable_against_in_memory_db()
+    {
+        var db = NewInMemoryDbFactory();
+        var actor = Sys.ActorOf(DbHealthProbeActor.Props(db));
+
+        var status = await actor.Ask<DbHealthProbeActor.DbHealthStatus>(
+            DbHealthProbeActor.GetStatus.Instance, TimeSpan.FromSeconds(3));
+
+        status.Reachable.ShouldBeTrue();
+        status.LastError.ShouldBeNull();
+    }
+
+    [Fact]
+    public void PeerOpcUaProbeActor_publishes_probe_result_at_each_tick()
+    {
+        var received = new System.Collections.Generic.List<object>();
+        var actor = Sys.ActorOf(PeerOpcUaProbeActor.Props(
+            NodeId.Parse("peer-1"),
+            interval: TimeSpan.FromMilliseconds(50),
+            broadcast: msg => received.Add(msg)));
+
+        AwaitCondition(() => received.Count >= 2, TimeSpan.FromSeconds(2));
+        received.OfType<PeerOpcUaProbeActor.OpcUaProbeResult>().ShouldNotBeEmpty();
+    }
+
+    [Fact]
+    public void HistorianAdapterActor_buffers_rows()
+    {
+        var actor = Sys.ActorOf(HistorianAdapterActor.Props());
+        for (var i = 0; i < 5; i++)
+            actor.Tell(new HistorianAdapterActor.HistoryRow("driver-a", $"tag-{i}", i, DateTime.UtcNow));
+
+        ExpectNoMsg(TimeSpan.FromMilliseconds(100));
+        // No direct readback of the count from a sealed actor — assert by Ask of a self-probe later
+        // when the engine wiring lands (F11). For now this asserts the actor accepts the contract.
+    }
+}