Redis is configured to save RDB snapshots

环境：centos7+nginx+php-fpm+redis+memcached

网站：xx.dragon.com

场景：早上开始，网站叮咣的一通告警，直接503.重启了服务不行，果断清了缓存。但没过多久又出现同样的问题

经查php告警日志发现：

php报错：

[05-Sep-2017 09:43:49] WARNING: [pool dragon] child 14321 said into stderr: "Stack trace:"
[05-Sep-2017 09:43:49] WARNING: [pool dragon] child 14321 said into stderr: "NOTICE: PHP message: PHP Fatal error:  Uncaught exception 'RedisException' with message 'MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.' in /vendor/snc/redis-bundle/Session/Storage/Handler/RedisSessionHandler.php:211"

redis日志：