using popen return codes to check whether the delete command was successfull, instead of stderr

xtreemfs_client/OSDManager.py

@@ -232,7 +232,8 @@ class OSDManager(object):
                 div_util.print_process_list(processes)
 
             for process in processes:
-                if process[1][1] == b'':
+                # check the return code. if it is one, the replica could not be deleted, so we try again later.
+                if not process[2]:
                     pass
                 else:
                     errored_deletions.append(process[0])

xtreemfs_client/div_util.py

@@ -47,7 +47,7 @@ def run_commands(commands, max_processes=200):
     for p in running_processes:
         p.wait()
 
-    return list(map(lambda proc: (proc.args, proc.communicate()), all_processes))
+    return list(map(lambda proc: (proc.args, proc.communicate(), proc.returncode), all_processes))
 
 
 def print_process_list(processes):