Address PR Comments

Signed-off-by: Harish Bhakuni <hbhakuni@amazon.com>

Author: Harish Bhakuni

server/src/main/java/org/opensearch/repositories/RepositoriesService.java

@@ -35,6 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.Version;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.action.admin.cluster.repositories.delete.DeleteRepositoryRequest;
@@ -79,6 +80,8 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import static org.opensearch.repositories.blobstore.BlobStoreRepository.REMOTE_STORE_INDEX_SHALLOW_COPY;
+
 /**
  * Service responsible for maintaining and providing access to snapshot repositories on nodes.
  *
@@ -160,6 +163,7 @@ public void registerRepository(final PutRepositoryRequest request, final ActionL
 
         final RepositoryMetadata newRepositoryMetadata = new RepositoryMetadata(request.name(), request.type(), request.settings());
         validate(request.name());
+        validateRepositoryMetadataSettings(clusterService, request.name(), request.settings());
 
         final ActionListener<ClusterStateUpdateResponse> registrationListener;
         if (request.verify()) {
@@ -605,6 +609,26 @@ private static void validate(final String repositoryName) {
         }
     }
 
+    public static void validateRepositoryMetadataSettings(
+        ClusterService clusterService,
+        final String repositoryName,
+        final Settings repositoryMetadataSettings
+    ) {
+        // We can add more validations here for repository settings in the future.
+        Version minVersionInCluster = clusterService.state().getNodes().getMinNodeVersion();
+        if (REMOTE_STORE_INDEX_SHALLOW_COPY.get(repositoryMetadataSettings) && !minVersionInCluster.onOrAfter(Version.V_2_9_0)) {
+            throw new RepositoryException(
+                repositoryName,
+                "setting "
+                    + REMOTE_STORE_INDEX_SHALLOW_COPY.getKey()
+                    + " cannot be enabled as some of the nodes in cluster are on version older than "
+                    + Version.V_2_9_0
+                    + ". Minimum node version in cluster is: "
+                    + minVersionInCluster
+            );
+        }
+    }
+
     private static void ensureRepositoryNotInUse(ClusterState clusterState, String repository) {
         if (isRepositoryInUse(clusterState, repository)) {
             throw new IllegalStateException("trying to modify or unregister repository that is currently used");

server/src/main/java/org/opensearch/snapshots/SnapshotShardsService.java

@@ -394,7 +394,7 @@ private void snapshot(
             GatedCloseable<IndexCommit> wrappedSnapshot = null;
             try {
                 if (remoteStoreIndexShallowCopy && indexShard.indexSettings().isRemoteStoreEnabled()) {
-                    long startTime = threadPool.absoluteTimeInMillis();
+                    long startTime = threadPool.relativeTimeInMillis();
                     // we flush first to make sure we get the latest writes snapshotted
                     wrappedSnapshot = indexShard.acquireLastIndexCommitAndRefresh(true);
                     long primaryTerm = indexShard.getOperationPrimaryTerm();
@@ -426,7 +426,7 @@ private void snapshot(
                         indexShard.releaseLockOnCommitData(snapshot.getSnapshotId().getUUID(), primaryTerm, commitGeneration);
                         throw e;
                     }
-                    long endTime = threadPool.absoluteTimeInMillis();
+                    long endTime = threadPool.relativeTimeInMillis();
                     logger.debug(
                         "Time taken (in milliseconds) to complete shallow copy snapshot, "
                             + "for index "

server/src/main/java/org/opensearch/snapshots/SnapshotsService.java

@@ -338,16 +338,6 @@ public ClusterState execute(ClusterState currentState) {
                 }
 
                 boolean remoteStoreIndexShallowCopy = REMOTE_STORE_INDEX_SHALLOW_COPY.get(repository.getMetadata().settings());
-                Version minVersionInCluster = currentState.nodes().getMinNodeVersion();
-                if (remoteStoreIndexShallowCopy && !minVersionInCluster.onOrAfter(Version.V_2_9_0)) {
-                    remoteStoreIndexShallowCopy = false;
-                    logger.warn(
-                        "Setting {} is ignored as some of the nodes in cluster are on version older than {}. Minimum node version in cluster is: {}",
-                        REMOTE_STORE_INDEX_SHALLOW_COPY,
-                        Version.V_2_9_0,
-                        minVersionInCluster
-                    );
-                }
                 newEntry = SnapshotsInProgress.startedEntry(
                     new Snapshot(repositoryName, snapshotId),
                     request.includeGlobalState(),