MongoDB备份方案随笔-slavedelay

mongodb中副本集的备份节点（非secondary节点）提供了一个功能，延时备份 单位是秒，这个作为延时备份的方案，在预防逻辑错误造成的数据丢失上有很大的意义，解决了mongodb备份方案简陋，没有增量备份的一个难题。

 

原理，备份节点实时从主节点取回oplog日志数据，按照时间戳延时执行到本地，完成数据延后备份。

 

附：mongodb，副本集参数释义

 

 

Member options

Each member can be configured to have any of the following options.

Command	Default	Description	Min Version
arbiterOnly	false	If true, this member will participate in vote but receive no data.	1.6
buildIndexes	true	When false, prevent secondary indexes from being created on this member. This is typically used on machines that are pure "backup" machines that are never queried. By not having the secondary indexes, the member performs less works on writes and requires less ram. Note the _id index is still created. Can only be set to false if priority:0. It is rare to use this option.	1.6
hidden	false	If true, do not advertise the member's existence to clients in isMaster command responses. It is rare to use this option.	1.7
priority	1.0	Priority of the server for elections. Higher priority servers will be preferred as primary. ()	1.6, 1.9
tags	[]	An array of strings representing the location of this server. These can be used for location-aware write guarantees, see	1.9.1
slaveDelay	0	Number of seconds to remain behind the primary. A value of 0 implies "as up-to-date as possible". Used to recover from human errors (e.g.: accidentally dropping a database). Can only be set on members with priority 0. Slave delay members are a great way to keep a rolling backup from a certain amount of time in the past.	1.6.3
votes	1	Number of votes this member has in an election. Generally you should not change this. ()	1.6