MongoDb双机房容灾啦

机房意外断电断网不得不预防，下面模拟测试某机房断电断网，B机房断电断网后A机房可正常提供服务，A机房断电断网后可能需要强制重启继续提供服务了，目前查看数据都还在，暂时没验证是否有数据丢失，小试了一把。。。

大概架构

A机房

192.168.70.214:27017 (为primary，其他节点都是SECONDARY)

192.168.70.215:27017

192.168.70.216:27017

B机房

192.168.71.214:27017

192.168.71.215:27017

下面重点记录下A机房断电断网，B机房怎么重启继续提供服务，其实主要就3步，见粗体

repset:SECONDARY> use admin

switched to db admin

repset:SECONDARY> cfg=rs.conf()

{

"_id" : "repset",

"version" : 79,

"members" : [

{

"_id" : 4,

"host" : "192.168.71.214:27017",

"priority" : 10

},

{

"_id" : 5,

"host" : "192.168.71.215:27017",

"priority" : 9

},

{

"_id" : 7,

"host" : "192.168.70.214:27017",

"priority" : 11

},

{

"_id" : 8,

"host" : "192.168.70.215:27017",

"priority" : 6

},

{

"_id" : 13,

"host" : "192.168.70.216:27017",

"priority" : 5

}

]

}

repset:SECONDARY> cfg.members = [cfg.members[0], cfg.members[1]]

[

{

"_id" : 4,

"host" : "192.168.71.214:27017",

"priority" : 10

},

{

"_id" : 5,

"host" : "192.168.71.215:27017",

"priority" : 9

}

]

repset:SECONDARY> rs.reconfig(cfg, {force :true })

{ "ok" : 1 }

repset:SECONDARY> rs.status()

{

"set" : "repset",

"date" : ISODate("2018-11-09T03:45:29Z"),

"myState" : 1,

"members" : [

{

"_id" : 4,

"name" : "192.168.71.214:27017",

"health" : 1,

"state" : 1,

"stateStr" : "PRIMARY",

"uptime" : 69133,

"optime" : Timestamp(1541663971000, 1),

"optimeDate" : ISODate("2018-11-08T07:59:31Z"),

"self" : true

},

{

"_id" : 5,

"name" : "192.168.71.215:27017",

"health" : 1,

"state" : 2,

"stateStr" : "SECONDARY",

"uptime" : 8,

"optime" : Timestamp(1541663971000, 1),

"optimeDate" : ISODate("2018-11-08T07:59:31Z"),

"lastHeartbeat" : ISODate("2018-11-09T03:45:29Z"),

"pingMs" : 0

}

],

"ok" : 1

}

repset:PRIMARY>

repset:PRIMARY> use test

switched to db test

repset:PRIMARY> show collections

system.indexes

test

testdb

repset:PRIMARY> rs.conf()

{

"_id" : "repset",

"version" : 38342,

"members" : [

{

"_id" : 4,

"host" : "192.168.71.214:27017",

"priority" : 10

},

{

"_id" : 5,

"host" : "192.168.71.215:27017",

"priority" : 9

}

]

}

从上面观察验证：新选的PRIMARY可以持续提供服务了，之前的数据都还在，解决了单机房断电断网的故障。

欢迎各位提供指导，共同成长。