SERVER-42573 Only warn about enableReadConcernMajority if PSA architecture

(cherry picked from commit 897ebf0eb55ffc68ef4c09aefc43a48bca82df3d)

3 files changed, 15 insertions, 2 deletions

diff --git a/src/mongo/db/repl/repl_set_config.cpp b/src/mongo/db/repl/repl_set_config.cpp
index 34fe0a2feff..00a8177cbf1 100644
--- a/src/mongo/db/repl/repl_set_config.cpp
+++ b/src/mongo/db/repl/repl_set_config.cpp
@@ -730,6 +730,12 @@ Status ReplSetConfig::checkIfWriteConcernCanBeSatisfied(
     }
 }
 
+int ReplSetConfig::getNumDataBearingMembers() const {
+    int numArbiters =
+        std::count_if(begin(_members), end(_members), [](const auto& x) { return x.isArbiter(); });
+    return _members.size() - numArbiters;
+}
+
 const MemberConfig& ReplSetConfig::getMemberAt(size_t i) const {
     invariant(i < _members.size());
     return _members[i];
diff --git a/src/mongo/db/repl/repl_set_config.h b/src/mongo/db/repl/repl_set_config.h
index 1e451a968ca..54ea0d52454 100644
--- a/src/mongo/db/repl/repl_set_config.h
+++ b/src/mongo/db/repl/repl_set_config.h
@@ -161,6 +161,11 @@ public:
     }
 
     /**
+     * Gets the number of data-bearing members in this configuration.
+     */
+    int getNumDataBearingMembers() const;
+
+    /**
      * Access a MemberConfig element by index.
      */
     const MemberConfig& getMemberAt(size_t i) const;
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index f7d410fdfbe..c6fb608d76b 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -562,9 +562,11 @@ void ReplicationCoordinatorImpl::_finishLoadLocalConfig(
         myIndex = StatusWith<int>(-1);
     }
 
-    if (serverGlobalParams.enableMajorityReadConcern && localConfig.containsArbiter()) {
+    if (serverGlobalParams.enableMajorityReadConcern && localConfig.getNumMembers() == 3 &&
+        localConfig.getNumDataBearingMembers() == 2) {
         log() << startupWarningsLog;
-        log() << "** WARNING: This replica set uses arbiters, but readConcern:majority is enabled "
+        log() << "** WARNING: This replica set has a Primary-Secondary-Arbiter architecture, but "
+                 "readConcern:majority is enabled "
               << startupWarningsLog;
         log() << "**          for this node. This is not a recommended configuration. Please see "
               << startupWarningsLog;