The FSMasterDirectoryProvider has a hole in the startup procedure where it is possible for the FSSlaveDirectoryProvider to not being able to find the current marker file. At the moment the startup for the slave will fail in this case. We could let the FSSlaveDirectoryProvider retry for a couple of times to allow the master to create the marker file.
This problem can also occur during runtime, but there the FSSlaveDirectoryProvider just skips a sync. However, we log this as error. Probably should just be a warning.