主从数据不一致引起的重大故障!请各位注意!
故障描述:主从架构,主宕机后,切换到了从,结果从上数据丢失了很多(在没宕机前未校验数据一致性),当时同步没有延时,用户登录时,无法在数据库中验证,结果
故障描述:主从架构,主宕机后,切换到了从,结果从上数据丢失了很多(在没宕机前未校验数据一致性),当时同步没有延时,用户登录时,无法在数据库中验证,结果大批用户无法登陆,导致投诉。
之前我写过一个PPT,是如何校验主从数据是否一致性。
主从同步正常,香港虚拟主机,并不代表主从数据一致性,香港虚拟主机,为什么?我举例说明一下:
主库上有a用户,密码123456,香港虚拟主机,从库上没有该用户。如果a用户一直不更新密码,从库上你用show slave status\G,发现是没有任何报错信息的,因为没有触发这条记录。不信,你可以试试。
所以才会有下面这个工具的存在:(注意!这个工具会锁表,表越大,锁住的时间也会越长)
注:主从架构,必须要保证数据的一致性,避免造成今天我这边的特大故障!
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