# 备份

对于一切生产系统（含开发测试环境），有效的备份和恢复是数据的最后保障。

每个运维人员在备份和恢复上都有着血泪史，如果没有有效的备份，并且没有后备系统切换，当出现故障时，每敲一条命令，操作者的手都会**颤抖**。

> `有效`是指数据备份和恢复是完整的，并且能够在满足业务需求下实现系统重建。不仅要关注数据的准确性，而且要关注时效性。如果出现故障，不能在SLA要求的时间范围内从备份恢复出系统，备份的价值就达达降低了。
>
> 请不要完全依赖备份，正确的方法是建立容灾系统，在故障时可以主备平滑切换且对业务无影响。备份是最后的保障，我们希望永远不要依靠备份来重建系统。


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