diff --git a/vcsserver/lib/rc_cache/archive_cache/fanout_cache.py b/vcsserver/lib/rc_cache/archive_cache/fanout_cache.py
--- a/vcsserver/lib/rc_cache/archive_cache/fanout_cache.py
+++ b/vcsserver/lib/rc_cache/archive_cache/fanout_cache.py
@@ -138,6 +138,13 @@ class FileSystemCache:
                 for chunk in iterator:
                     size += len(chunk)
                     writer.write(chunk)
+                writer.flush()
+                # Get the file descriptor
+                fd = writer.fileno()
+
+                # Sync the file descriptor to disk, helps with NFS cases...
+                os.fsync(fd)
+                log.debug('written new archive cache under %s', full_path)
                 return size
 
     def _get_keyfile(self, key):