nginx session无法存到服务器

x798667323

$config['sess_driver'] = 'files';
$config['sess_cookie_name'] = 'ci_session';
$config['sess_expiration'] = 43200;
// $config['sess_save_path'] = APPPATH.'data';
$config['sess_save_path'] = BASEPATH.'../'.'session_file';
$config['sess_match_ip'] = FALSE;
$config['sess_time_to_update'] = 300;
$config['sess_regenerate_destroy'] = FALSE;

ci框架 本地能存入session文件

nginx 上无法存入session文件
是什么原因