mongodb 副本集

系统：centos6.5

IP：10.19.21.244 主节点

10.19.21.245 备节点

10.19.21.248 仲裁点

不只是主节点、副本节点、仲裁节点，还有Secondary-Only、Hidden、Delayed、Non-Voting。

Secondary-Only:不能成为primary节点，只能作为secondary副本节点，防止一些性能不高的节点成为主节点。

Hidden:这类节点是不能够被客户端制定IP引用，也不能被设置为主节点，但是可以投票，一般用于备份数据。

Delayed：可以指定一个时间延迟从primary节点同步数据。主要用于备份数据，如果实时同步，误删除数据马上同步到从节点，恢复又恢复不了。

Non-Voting：没有选举权的secondary节点，纯粹的备份数据节点。

三台主机安装mongodb

下载mongodbwget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-2.6.9.tgz解压到目录tar xf mongodb-linux-x86_64-2.6.9.tgz -C /usr/local/src更改名mv mongodb-linux-x86_64-2.6.9 /usr/local/mongodbcd /usr/local/mongodb/创建数据目录和日志目录mkdir -p data log创建用户useradd mongodb -s /sbin/nologin更改目录属主属组chown mongod:mongodb /usr/local/mongodb -R更改环境变量vim ~/.bash_profilePATH=$PATH:/usr/local/mongodb/binsource ~/.bash_profile

配置文件vim /etc/mongodb.confport = 27017fork = truelogpath = /usr/local/mongodb/log/mongodb.logdbpath =/usr/local/mongodb/data/journal = true#以目录的形式存数据，如果已经存在，修改此配置会导致原始数据消失（注释次参数会回来），除非迁移现有数据文件到directoryperdb所产生的数据目录中。directoryperdb=true#日志增加形式写入logappend=true#配置副本集，指定副本名称作为参数，所有主机都必须有相同名称作为同一个副本集replSet=testrs#使用预分配方式来保证写入性能的稳定，预分配在后台进行，并且每个预分配的文件都用0进行填充。这会让MongoDB始终保持额外的空间和空余的数据文件，从而避免了数据增长过快而带来的分配磁盘空间引起的阻塞。设置noprealloc= true来禁用预分配的数据文件，会缩短启动时间，但在正常操作过程中，可能会导致性能显著下降。noprealloc=true

启动服务mongod -f /etc/mongodb.conf

首先连接主节点mongo> use admin> conf = {_id:"testrs",members:[{_id:0,host:"10.19.21.244:27017",priority:2},{_id:1,host:"10.19.21.245:27017",priority:1},{_id:2,host:"10.19.21.248:27017",arbiterOnly:true}]};{        "_id" : "testrs",        "version" : 1,        "members" : [                {                        "_id" : 0,                        "host" : "10.19.21.244:27017",                        "priority" : 2                },                {                        "_id" : 1,                        "host" : "10.19.21.245:27017"                },                {                        "_id" : 2,                        "host" : "10.19.21.248:27017",                        "arbiterOnly" : true                }        ]}注意最初的_id的值就是我们配置文件中设定的replSet的值，arbiterOnly是大写的O，配置完成后进行初始化：> rs.initiate(conf){        "info" : "Config now saved locally.  Should come online in about a minute.",        "ok" : 1}此步骤必须备节点和仲裁节点的mongo启动，不然无法执行此步骤。

> rs.status(){        "set" : "testrs",        "date" : ISODate("2015-05-07T11:55:17Z"),        "myState" : 1,        "members" : [                {                        "_id" : 0,                        "name" : "10.19.21.244:27017",                        "health" : 1,                        "state" : 1,                        "stateStr" : "PRIMARY",                        "uptime" : 5737,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "electionTime" : Timestamp(1430993992, 1),                        "electionDate" : ISODate("2015-05-07T10:19:52Z"),                        "self" : true                },                {                        "_id" : 1,                        "name" : "10.19.21.245:27017",                        "health" : 1,                        "state" : 2,                        "stateStr" : "SECONDARY",                        "uptime" : 3077,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "lastHeartbeat" : ISODate("2015-05-07T11:55:17Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T11:55:17Z"),                        "pingMs" : 0,                        "syncingTo" : "10.19.21.244:27017"                },                {                        "_id" : 2,                        "name" : "10.19.21.248:27017",                        "health" : 1,                        "state" : 7,                        "stateStr" : "ARBITER",                        "uptime" : 5735,                        "lastHeartbeat" : ISODate("2015-05-07T11:55:17Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T11:55:17Z"),                        "pingMs" : 0                }        ],        "ok" : 1}

> use test插入数据> db.testdb.insert({"tset1":"i'm master"})

然后到备份节点查看数据是否有mongo 10.19.21.245testrs:SECONDARY> use testswitched to db testtestrs:SECONDARY> show tables;2015-05-07T19:57:29.670+0800 error: { "$err" : "not master and slaveOk=false", "code" : 13435 } at src/mongo/shell/query.js:131需要进行配置testrs:SECONDARY> db.setSlaveOk()testrs:SECONDARY> show tables;system.indexestestdbtestrs:SECONDARY> db.testdb.find(){ "_id" : ObjectId("554a4ee4eb804a0f1b6ec347"), "test1" : "i'm master" }

停止主节点，查看整个集群状态testrs:PRIMARY> rs.status(){        "set" : "testrs",        "date" : ISODate("2015-05-07T11:59:42Z"),        "myState" : 1,        "members" : [                {                        "_id" : 0,                        "name" : "10.19.21.244:27017",                        "health" : 0,                        "state" : 8,                        "stateStr" : "(not reachable/healthy)",                        "uptime" : 0,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "lastHeartbeat" : ISODate("2015-05-07T11:59:40Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T11:59:32Z"),                        "pingMs" : 0                },                {                        "_id" : 1,                        "name" : "10.19.21.245:27017",                        "health" : 1,                        "state" : 1,                        "stateStr" : "PRIMARY",                        "uptime" : 3342,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "electionTime" : Timestamp(1430999976, 1),                        "electionDate" : ISODate("2015-05-07T11:59:36Z"),                        "self" : true                },                {                        "_id" : 2,                        "name" : "10.19.21.248:27017",                        "health" : 1,                        "state" : 7,                        "stateStr" : "ARBITER",                        "uptime" : 3340,                        "lastHeartbeat" : ISODate("2015-05-07T11:59:42Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T11:59:41Z"),                        "pingMs" : 0                }        ],        "ok" : 1}

主节点已切换过来，此时备节点已经变成了主节点。再插入一条数据testrs:PRIMARY> db.testdb.insert({"test2":"i'm new master"})testrs:PRIMARY> db.testdb.find();{ "_id" : ObjectId("554a4ee4eb804a0f1b6ec347"), "test1" : "i'm master" }{ "_id" : ObjectId("554a505d494f70c600422b41"), "test2" : "i'm new master" }

重启原来的主节点查看状态testrs:SECONDARY> rs.status(){        "set" : "testrs",        "date" : ISODate("2015-05-07T14:00:33Z"),        "myState" : 1,        "members" : [                {                        "_id" : 0,                        "name" : "10.19.21.244:27017",                        "health" : 1,                        "state" : 1,                        "stateStr" : "PRIMARY",                        "uptime" : 15,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "electionTime" : Timestamp(1431007222, 1),                        "electionDate" : ISODate("2015-05-07T14:00:22Z"),                        "self" : true                },                {                        "_id" : 1,                        "name" : "10.19.21.245:27017",                        "health" : 1,                        "state" : 2,                        "stateStr" : "SECONDARY",                        "uptime" : 13,                        "optime" : Timestamp(1430995665, 1),                        "optimeDate" : ISODate("2015-05-07T10:47:45Z"),                        "lastHeartbeat" : ISODate("2015-05-07T14:00:32Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T14:00:33Z"),                        "pingMs" : 0,                        "lastHeartbeatMessage" : "syncing to: 10.19.21.244:27017",                        "syncingTo" : "10.19.21.244:27017"                },                {                        "_id" : 2,                        "name" : "10.19.21.248:27017",                        "health" : 1,                        "state" : 7,                        "stateStr" : "ARBITER",                        "uptime" : 13,                        "lastHeartbeat" : ISODate("2015-05-07T14:00:32Z"),                        "lastHeartbeatRecv" : ISODate("2015-05-07T14:00:33Z"),                        "pingMs" : 0                }        ],        "ok" : 1}

查看数据是否同步过来testrs:PRIMARY> use testswitched to db testtestrs:PRIMARY> db.testdb.find(){ "_id" : ObjectId("554a4ee4eb804a0f1b6ec347"), "test1" : "i'm master" }{ "_id" : ObjectId("554a505d494f70c600422b41"), "test2" : "i'm new master" }

向集群中增加节点cfg = rs.conf()cfg.members[3] = {_id:3,host:"10.19.21.246:27017",priority:0.5}rs.reconfig(cfg)如果备份节点无法读取数据，需要设置db.setSlaveOK()。如果备份节点可读但不可写，修改优先级cfg = rs.conf()cfg.members[0].priority = 0.5cfg.members[1].priority = 2cfg.members[2].priority = 2rs.reconfig(cfg)需要 reconfig后配置才能生效。

php与mongodb连接 'testrs',        'readPreference' => 'secondaryPreferred',);$m = new MongoClient("mongodb://10.19.21.244:27017,10.19.21.245:27017/", $options);foreach ( $m->getConnections() as $c ){    echo $c['hash'], ":\n",    " - {$c['connection']['connection_type_desc']}, ",    "{$c['connection']['ping_ms']} ms\n";}?>

primary:默认参数，只从主节点上进行读取操作；

primaryPreferred:大部分从主节点上读取数据,只有主节点不可用时从secondary节点读取数据。

secondary:只从secondary节点上进行读取操作，存在的问题是secondary节点的数据会比primary节点数据"旧"。

secondaryPreferred:优先从secondary节点进行读取操作，secondary节点不可用时从主节点读取数据；

nearest:不管是主节点、secondary节点，从网络延迟最低的节点上读取数据。