MongoDB副本集
一、节点类型
standard：常规节点，它存储一份完整的数据副本，参与选举投票，有可能成为活跃节点。
passive：存储了完整的数据副本，参与投票，不能成为活跃节点。
arbiter：仲裁节点，只参与投票，不接收复制的数据，也不能成为活跃节点。
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二、参数说明--dbpath?? 数据文件路径
--logpath? 日志文件路径
--port??????? 端口号，默认是27017.我这里使用的也是这个端口号.
--replSet?? 复制集的名字，一个replica sets中的每个节点的这个参数都要用一个复制集名字，这里是test.
--replSet ? 这个后面跟的是其他standard节点的ip和端口
--maxConns?? 最大连接数
--fork?????? 后台运行
--logappend?? 日志文件循环使用，如果日志文件已满，那么新日志覆盖最久日志。
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三、创建副本集环境说明:ip:10.0.0.3ip:10.0.0.4ip:10.0.0.5?启动第一个standard节点（ip:10.0.0.3)
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hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/loghww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
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启动第一个standard节点（ip:10.0.0.4)hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/loghww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
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启动arbiter节点，也就是仲裁节点 （ip:10.0.0.5)hww@ubuntu:~$ mkdir -p ~/mongo/db ~/mongo/loghww@ubuntu:~$ mongod -dbpath ~/mongo/db -logpath ~/mongo/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend
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启动了以上服务器后，日志告诉你副本集没有初始化。因为还差最后一步：在shell中初始化副本集。
连接其中一台standard节点服务器。初始化命令只能执行一次：
hww@ubuntu:~$ mongo 10.0.0.3:27037/adminMongoDB shell version: 2.0.1connecting to: 10.0.0.3:27037/admin> db.runCommand({"replSetInitiate" : {... "_id" : "test",... "members" : [... {... "_id" : 0,... "host" : "10.0.0.3:27037"... },... {... "_id" : 1,... "host" : "10.0.0.4:27037"... }... ]}}){ "info" : "Config now saved locally. Should come online in about a minute.", "ok" : 1}> 执行以下shell命令后，如果看见红色字体标记的内容，则表示初始化成功? shell命令：
db.runCommand({"replSetInitiate" : { "_id" : "test", "members" : [ { "_id" : 0, "host" : "10.0.0.3:27037" }, { "_id" : 1, "host" : "10.0.0.4:27037" } ]}})你也可以通过命令查看效果：
> rs.status(){ "set" : "test", "date" : ISODate("2011-12-06T07:44:29Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "10.0.0.3:27037", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "optime" : { "t" : 1323157008000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:36:48Z"), "self" : true }, { "_id" : 1, "name" : "10.0.0.4:27037", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 455, "optime" : { "t" : 1323157008000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:36:48Z"), "lastHeartbeat" : ISODate("2011-12-06T07:44:28Z"), "pingMs" : 2 } ], "ok" : 1}?加入仲裁节点执行以下命令：
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PRIMARY> rs.addArb("10.0.0.5:27037");{ "ok" : 1 }?我们可以再次查看当前状态：
PRIMARY> rs.status(){ "set" : "test", "date" : ISODate("2011-12-06T07:46:21Z"), "myState" : 1, "members" : [ { "_id" : 0, "name" : "10.0.0.3:27037", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "optime" : { "t" : 1323157549000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:45:49Z"), "self" : true }, { "_id" : 1, "name" : "10.0.0.4:27037", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 567, "optime" : {PRIMARY> db.isMaster();{ "setName" : "test", "ismaster" : true, "secondary" : false, "hosts" : [ "10.0.0.3:27037", "10.0.0.4:27037" ], "arbiters" : [ "10.0.0.5:27037" ], "primary" : "10.0.0.3:27037", "me" : "10.0.0.3:27037", "maxBsonObjectSize" : 16777216, "ok" : 1}? "t" : 1323157549000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:45:49Z"), "lastHeartbeat" : ISODate("2011-12-06T07:46:20Z"), "pingMs" : 0 }, { "_id" : 2, "name" : "10.0.0.5:27037", "health" : 1, "state" : 7, "stateStr" : "ARBITER", "uptime" : 22, "optime" : { "t" : 0, "i" : 0 }, "optimeDate" : ISODate("1970-01-01T00:00:00Z"), "lastHeartbeat" : ISODate("2011-12-06T07:46:19Z"), "pingMs" : 0 } ], "ok" : 1}?? rs.status()通过这个命令，可以查看各个节点的ip、角色已经是否正常
?? 我们看到已经成功配置。
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查看活跃节点：PRIMARY> db.isMaster();{ "setName" : "test", "ismaster" : true, "secondary" : false, "hosts" : [ "10.0.0.3:27037", "10.0.0.4:27037" ], "arbiters" : [ "10.0.0.5:27037" ], "primary" : "10.0.0.3:27037", "me" : "10.0.0.3:27037", "maxBsonObjectSize" : 16777216, "ok" : 1}??? 可以看到现在10.0.0.3：27037为活跃节点。
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检测是否配置成功?? 可以强制primary和standard节点角色互换，从而验证是否能够实现副本集功能
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rs.stepDown()
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?? 执行完成后：
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SECONDARY> db.isMaster();{ "setName" : "test", "ismaster" : false, "secondary" : true, "hosts" : [ "10.0.0.3:27037", "10.0.0.4:27037" ], "arbiters" : [ "10.0.0.5:27037" ], "primary" : "10.0.0.4:27037", "me" : "10.0.0.3:27037", "maxBsonObjectSize" : 16777216, "ok" : 1}?? 可以看到现在主节点已经修改为10.0.0.4：27037了。
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?我们也可以动态扩展增加节点（ip:10.0.0.5:27047）?
hww@ubuntu:~$ mkdir -p ~/mongo1/db ~/mongo1/loghww@ubuntu:~$ mongod -dbpath ~/mongo1/db -logpath ~/mongo1/log/mongod.log -port 27037 -replSet test -maxConns=2000 -fork -logappend?
? 进入活跃节点的服务器
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hww@ubuntu4:~$ mongo 10.0.0.4:27037/adminMongoDB shell version: 2.0.1connecting to: 10.0.0.4:27037/adminPRIMARY> rs.add("10.0.0.5:27047");{ "ok" : 1 }PRIMARY> ?PRIMARY> rs.status(){ "set" : "test", "date" : ISODate("2011-12-06T07:59:36Z"), "myState" : 1, "syncingTo" : "10.0.0.3:27037", "members" : [ { "_id" : 0, "name" : "10.0.0.3:27037", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 1263, "optime" : { "t" : 1323158245000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:57:25Z"), "lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"), "pingMs" : 0 }, { "_id" : 1, "name" : "10.0.0.4:27037", "health" : 1, "state" : 1, "stateStr" : "PRIMARY", "optime" : { "t" : 1323158245000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:57:25Z"), "self" : true }, { "_id" : 2, "name" : "10.0.0.5:27037", "health" : 1, "state" : 7, "stateStr" : "ARBITER", "uptime" : 717, "optime" : { "t" : 0, "i" : 0 }, "optimeDate" : ISODate("1970-01-01T00:00:00Z"), "lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"), "pingMs" : 0 }, { "_id" : 3, "name" : "10.0.0.5:27047", "health" : 1, "state" : 2, "stateStr" : "SECONDARY", "uptime" : 125, "optime" : { "t" : 1323158245000, "i" : 1 }, "optimeDate" : ISODate("2011-12-06T07:57:25Z"), "lastHeartbeat" : ISODate("2011-12-06T07:59:35Z"), "pingMs" : 0 } ], "ok" : 1}?
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