diff --git a/hubstorage/batchuploader.py b/hubstorage/batchuploader.py
index 58ca8f5..ba86d6f 100644
--- a/hubstorage/batchuploader.py
+++ b/hubstorage/batchuploader.py
@@ -146,10 +146,13 @@ def _tryupload(self, batch):
         url = batch['url']
         offset = batch['offset']
         for retryn in xrange(self.worker_max_retries):
-            emsg = ''
             try:
                 r = self._upload(batch)
-                r.raise_for_status()
+
+                if r.status_code == 429 or (500 <= r.status_code < 600):
+                    http_error_msg = '%s Server Error: %s' % (r.status_code, r.reason)
+                    raise requests.HTTPError(http_error_msg, response=r)
+
                 if not (200 <= r.status_code < 300):
                     logger.warning('Discarding write to url=%s offset=%s: '
                                    '[HTTP error %s] %s\n%s', url, offset,