var fdMu sync.Mutex
	fds := opts.fallbackDisks
	fallback := func(err error) StorageAPI {
		if _, ok := err.(StorageErr); ok {
			// Attempt to grab a fallback disk
			fdMu.Lock()
			defer fdMu.Unlock()
			if len(fds) == 0 {
				return nil
			}
			fdsCopy := fds
			for _, fd := range fdsCopy {
				// Grab a fallback disk
				fds = fds[1:]
				if fd != nil && fd.IsOnline() {