diff --git a/cpp/core/Msgs.cpp b/cpp/core/Msgs.cpp
index a326a01b..7b53f229 100644
--- a/cpp/core/Msgs.cpp
+++ b/cpp/core/Msgs.cpp
@@ -13,7 +13,7 @@ std::ostream& operator<<(std::ostream& out, ReplicaId replica) {
 }
 
 std::ostream& operator<<(std::ostream& out, ShardReplicaId shrid) {
-    out << shrid.shardId() << ":" << shrid.replicaId();
+    out << std::setw(3) << std::setfill('0') << shrid.shardId() << ":" << shrid.replicaId();
     return out;
 }
 
diff --git a/cpp/shard/Shard.cpp b/cpp/shard/Shard.cpp
index 707b074f..faade80a 100644
--- a/cpp/shard/Shard.cpp
+++ b/cpp/shard/Shard.cpp
@@ -170,7 +170,7 @@ struct ShardServer : Loop {
 private:
     // init data
     ShardShared& _shared;
-    ShardId _shid;
+    ShardReplicaId _shrid;
     std::array<IpPort, 2> _ipPorts;
     uint64_t _packetDropRand;
     uint64_t _incomingPacketDropProbability; // probability * 10,000
@@ -196,10 +196,10 @@ private:
     MultiplexedChannel<3, std::array<uint32_t, 3>{SHARD_REQ_PROTOCOL_VERSION, LOG_REQ_PROTOCOL_VERSION, LOG_RESP_PROTOCOL_VERSION}> _channel;
 
 public:
-    ShardServer(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardId shid, const ShardOptions& options, ShardShared& shared) :
+    ShardServer(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardReplicaId shrid, const ShardOptions& options, ShardShared& shared) :
         Loop(logger, xmon, "server"),
         _shared(shared),
-        _shid(shid),
+        _shrid(shrid),
         _ipPorts(options.ipPorts),
         _packetDropRand(eggsNow().ns),
         _incomingPacketDropProbability(0),
@@ -263,7 +263,7 @@ private:
             _shared.ports[i].store(ntohs(serverAddr.sin_port), std::memory_order_release);
             _shared.socks[i].fd = sock;
             _shared.socks[i].events = POLL_IN;
-            LOG_INFO(_env, "Bound shard %s to %s", _shid, serverAddr);
+            LOG_INFO(_env, "Bound shard %s to %s", _shrid, serverAddr);
 
             _recvBuf[i].resize(DEFAULT_UDP_MTU*MAX_RECV_MSGS);
             _recvHdrs[i].resize(MAX_RECV_MSGS);
@@ -705,17 +705,17 @@ public:
 struct ShardBlockServiceUpdater : PeriodicLoop {
 private:
     ShardShared& _shared;
-    ShardId _shid;
+    ShardReplicaId _shrid;
     std::string _shuckleHost;
     uint16_t _shucklePort;
     XmonNCAlert _alert;
     ShardRespContainer _respContainer;
     std::vector<QueuedShardLogEntry> _logEntries;
 public:
-    ShardBlockServiceUpdater(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardId shid, const ShardOptions& options, ShardShared& shared):
+    ShardBlockServiceUpdater(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardReplicaId shrid, const ShardOptions& options, ShardShared& shared):
         PeriodicLoop(logger, xmon, "bs_updater", {1_sec, 1_mins}),
         _shared(shared),
-        _shid(shid),
+        _shrid(shrid),
         _shuckleHost(options.shuckleHost),
         _shucklePort(options.shucklePort)
     {
@@ -728,7 +728,7 @@ public:
         auto& logEntry = _logEntries.emplace_back();
         logEntry.logEntry.time = eggsNow();
         auto& blockServicesEntry = logEntry.logEntry.body.setUpdateBlockServices();
-        std::string err = fetchBlockServices(_shuckleHost, _shucklePort, 10_sec, _shid, blockServicesEntry);
+        std::string err = fetchBlockServices(_shuckleHost, _shucklePort, 10_sec, _shrid.shardId(), blockServicesEntry);
         if (!err.empty()) {
             _env.updateAlert(_alert, "could not reach shuckle: %s", err);
             return false;
@@ -787,16 +787,16 @@ public:
 struct ShardStatsInserter : PeriodicLoop {
 private:
     ShardShared& _shared;
-    ShardId _shid;
+    ShardReplicaId _shrid;
     std::string _shuckleHost;
     uint16_t _shucklePort;
     XmonNCAlert _alert;
     std::vector<Stat> _stats;
 public:
-    ShardStatsInserter(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardId shid, const ShardOptions& options, ShardShared& shared):
+    ShardStatsInserter(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardReplicaId shrid, const ShardOptions& options, ShardShared& shared):
         PeriodicLoop(logger, xmon, "stats", {1_mins, 1_hours}),
         _shared(shared),
-        _shid(shid),
+        _shrid(shrid),
         _shuckleHost(options.shuckleHost),
         _shucklePort(options.shucklePort),
         _alert(XmonAppType::DAYTIME)
@@ -807,7 +807,7 @@ public:
     virtual bool periodicStep() override {
         for (ShardMessageKind kind : allShardMessageKind) {
             std::ostringstream prefix;
-            prefix << "shard." << std::setw(3) << std::setfill('0') << _shid << "." << kind;
+            prefix << "shard." << _shrid << "." << kind;
             _shared.timings[(int)kind].toStats(prefix.str(), _stats);
             _shared.errors[(int)kind].toStats(prefix.str(), _stats);
         }
@@ -837,17 +837,17 @@ public:
 struct ShardMetricsInserter : PeriodicLoop {
 private:
     ShardShared& _shared;
-    ShardId _shid;
+    ShardReplicaId _shrid;
     XmonNCAlert _sendMetricsAlert;
     MetricsBuilder _metricsBuilder;
     std::unordered_map<std::string, uint64_t> _rocksDBStats;
     std::array<XmonNCAlert, 2> _sockQueueAlerts;
     XmonNCAlert _writeQueueAlert;
 public:
-    ShardMetricsInserter(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardId shid, ShardShared& shared):
+    ShardMetricsInserter(Logger& logger, std::shared_ptr<XmonAgent>& xmon, ShardReplicaId shrid, ShardShared& shared):
         PeriodicLoop(logger, xmon, "metrics", {1_sec, 1.0, 1_mins, 0.1}),
         _shared(shared),
-        _shid(shid),
+        _shrid(shrid),
         _sendMetricsAlert(XmonAppType::DAYTIME),
         _sockQueueAlerts({XmonAppType::NEVER, XmonAppType::NEVER}),
         _writeQueueAlert(XmonAppType::NEVER)
@@ -876,7 +876,7 @@ public:
                 uint64_t count = errs.count[i].load();
                 if (count == 0) { continue; }
                 _metricsBuilder.measurement("eggsfs_shard_requests");
-                _metricsBuilder.tag("shard", _shid);
+                _metricsBuilder.tag("shard", _shrid);
                 _metricsBuilder.tag("kind", kind);
                 _metricsBuilder.tag("write", !readOnlyShardReq(kind));
                 if (i == 0) {
@@ -890,20 +890,20 @@ public:
         }
         {
             _metricsBuilder.measurement("eggsfs_shard_write_queue");
-            _metricsBuilder.tag("shard", _shid);
+            _metricsBuilder.tag("shard", _shrid);
             _metricsBuilder.fieldFloat("size", _shared.logEntriesQueueSize);
             _metricsBuilder.timestamp(now);
         }
         for (int i = 0; i < _shared.receivedRequests.size(); i++) {
             _metricsBuilder.measurement("eggsfs_shard_received_requests");
-            _metricsBuilder.tag("shard", _shid);
+            _metricsBuilder.tag("shard", _shrid);
             _metricsBuilder.tag("socket", i);
             _metricsBuilder.fieldFloat("count", _shared.receivedRequests[i]);
             _metricsBuilder.timestamp(now);
         }
         {
             _metricsBuilder.measurement("eggsfs_shard_pulled_write_requests");
-            _metricsBuilder.tag("shard", _shid);
+            _metricsBuilder.tag("shard", _shrid);
             _metricsBuilder.fieldFloat("count", _shared.pulledWriteRequests);
             _metricsBuilder.timestamp(now);
         }
@@ -912,7 +912,7 @@ public:
             _shared.sharedDB.rocksDBMetrics(_rocksDBStats);
             for (const auto& [name, value]: _rocksDBStats) {
                 _metricsBuilder.measurement("eggsfs_shard_rocksdb");
-                _metricsBuilder.tag("shard", _shid);
+                _metricsBuilder.tag("shard", _shrid);
                 _metricsBuilder.fieldU64(name, value);
                 _metricsBuilder.timestamp(now);
             }
@@ -982,7 +982,7 @@ void runShard(ShardReplicaId shrid, const std::string& dbDir, const ShardOptions
         XmonConfig config;
         {
             std::ostringstream ss;
-            ss << std::setw(5) << std::setfill('0') << shrid;
+            ss << shrid;
             config.appInstance = "eggsshard" + ss.str();
         }
         config.prod = options.xmonProd;
@@ -1014,13 +1014,13 @@ void runShard(ShardReplicaId shrid, const std::string& dbDir, const ShardOptions
     env.clearAlert(dbInitAlert);
     ShardShared shared(sharedDB, shardDB);
 
-    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardServer>(logger, xmon, shrid.shardId(), options, shared)));
+    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardServer>(logger, xmon, shrid, options, shared)));
     threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardWriter>(logger, xmon, shrid, options, shared)));
     threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardRegisterer>(logger, xmon, shrid, options, shared)));
-    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardBlockServiceUpdater>(logger, xmon, shrid.shardId(), options, shared)));
-    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardStatsInserter>(logger, xmon, shrid.shardId(), options, shared)));
+    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardBlockServiceUpdater>(logger, xmon, shrid, options, shared)));
+    threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardStatsInserter>(logger, xmon, shrid, options, shared)));
     if (options.metrics) {
-        threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardMetricsInserter>(logger, xmon, shrid.shardId(), shared)));
+        threads.emplace_back(LoopThread::Spawn(std::make_unique<ShardMetricsInserter>(logger, xmon, shrid, shared)));
     }
 
     // from this point on termination on SIGINT/SIGTERM will be graceful