diff --git a/server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java b/server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java
index c8cdf0d4e0308..cde7a18d8c11c 100644
--- a/server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java
+++ b/server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java
@@ -211,9 +211,9 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     private final boolean readOnly;
 
-    private final ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshot> indexShardSnapshotFormat;
+    private ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshot> indexShardSnapshotFormat;
 
-    private final ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshots> indexShardSnapshotsFormat;
+    private ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshots> indexShardSnapshotsFormat;
 
     private final Object lock = new Object();
 
@@ -234,15 +234,6 @@ protected BlobStoreRepository(RepositoryMetaData metadata, Settings settings, Na
         snapshotRateLimiter = getRateLimiter(metadata.settings(), "max_snapshot_bytes_per_sec", new ByteSizeValue(40, ByteSizeUnit.MB));
         restoreRateLimiter = getRateLimiter(metadata.settings(), "max_restore_bytes_per_sec", new ByteSizeValue(40, ByteSizeUnit.MB));
         readOnly = metadata.settings().getAsBoolean("readonly", false);
-
-        indexShardSnapshotFormat = new ChecksumBlobStoreFormat<>(SNAPSHOT_CODEC, SNAPSHOT_NAME_FORMAT,
-            BlobStoreIndexShardSnapshot::fromXContent, namedXContentRegistry, isCompress());
-        indexShardSnapshotsFormat = new ChecksumBlobStoreFormat<>(SNAPSHOT_INDEX_CODEC, SNAPSHOT_INDEX_NAME_FORMAT,
-            BlobStoreIndexShardSnapshots::fromXContent, namedXContentRegistry, isCompress());
-        ByteSizeValue chunkSize = chunkSize();
-        if (chunkSize != null && chunkSize.getBytes() <= 0) {
-            throw new IllegalArgumentException("the chunk size cannot be negative: [" + chunkSize + "]");
-        }
     }
 
     @Override
@@ -253,6 +244,15 @@ protected void doStart() {
             IndexMetaData::fromXContent, namedXContentRegistry, isCompress());
         snapshotFormat = new ChecksumBlobStoreFormat<>(SNAPSHOT_CODEC, SNAPSHOT_NAME_FORMAT,
             SnapshotInfo::fromXContentInternal, namedXContentRegistry, isCompress());
+
+        indexShardSnapshotFormat = new ChecksumBlobStoreFormat<>(SNAPSHOT_CODEC, SNAPSHOT_NAME_FORMAT,
+            BlobStoreIndexShardSnapshot::fromXContent, namedXContentRegistry, isCompress());
+        indexShardSnapshotsFormat = new ChecksumBlobStoreFormat<>(SNAPSHOT_INDEX_CODEC, SNAPSHOT_INDEX_NAME_FORMAT,
+            BlobStoreIndexShardSnapshots::fromXContent, namedXContentRegistry, isCompress());
+        ByteSizeValue chunkSize = chunkSize();
+        if (chunkSize != null && chunkSize.getBytes() <= 0) {
+            throw new IllegalArgumentException("the chunk size cannot be negative: [" + chunkSize + "]");
+        }
     }
 
     @Override
diff --git a/server/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryTests.java b/server/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryTests.java
index 871e5071ec7b7..5f7a4afc78815 100644
--- a/server/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryTests.java
+++ b/server/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryTests.java
@@ -22,8 +22,13 @@
 import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
 import org.elasticsearch.client.Client;
+import org.elasticsearch.cluster.metadata.RepositoryMetaData;
 import org.elasticsearch.common.UUIDs;
+import org.elasticsearch.common.blobstore.BlobPath;
+import org.elasticsearch.common.blobstore.BlobStore;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeUnit;
+import org.elasticsearch.common.unit.ByteSizeValue;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.plugins.Plugin;
@@ -232,6 +237,49 @@ public void testIncompatibleSnapshotsBlobExists() throws Exception {
         assertEquals(0, repository.getRepositoryData().getIncompatibleSnapshotIds().size());
     }
 
+
+    public void testBlobStoreRepositoryConstructor() {
+        // simply check that compress and chunksize are not called (since they used to be) - they are not valid inside the constructor,
+        // call them in doStart() instead.
+        new BlobStoreRepository(new RepositoryMetaData("test", "test", Settings.EMPTY), Settings.EMPTY, null) {
+            @Override
+            protected boolean isCompress() {
+                fail("Not allowed to call isCompress in constructor");
+                return false;
+            }
+
+            @Override
+            protected ByteSizeValue chunkSize() {
+                fail("Not allowed to call chunkSize in constructor");
+                return null;
+            }
+
+            @Override
+            protected BlobStore createBlobStore() throws Exception {
+                throw new UnsupportedOperationException();
+            }
+
+            @Override
+            protected BlobPath basePath() {
+                throw new UnsupportedOperationException();
+            }
+        };
+    }
+
+    public void testBadChunksize() throws Exception {
+        final Client client = client();
+        final Path location = ESIntegTestCase.randomRepoPath(node().settings());
+        final String repositoryName = "test-repo";
+
+        expectThrows(RepositoryException.class, () ->
+            client.admin().cluster().preparePutRepository(repositoryName)
+                .setType(REPO_TYPE)
+                .setSettings(Settings.builder().put(node().settings())
+                    .put("location", location)
+                    .put("chunk_size", randomLongBetween(-10, 0), ByteSizeUnit.BYTES))
+                .get());
+    }
+
     private BlobStoreRepository setupRepo() {
         final Client client = client();
         final Path location = ESIntegTestCase.randomRepoPath(node().settings());