mongodb的安装及主从复制
一、mongodb安装1.下载mongodblinux版本（注意32位和64位的区别）wget http://downloads.mongodb.org/linux/mongodb-linux-x86_64-2.0.7.tgz2.解压
tar xvf mongodb-linux-x86_64-2.0.7.tgzmkdir /usr/local/mongodbmv mongodb-linux-x86_64-2.0.7/* /usr/local/mongodb
3.创建数据库文件目录如果有单独的分区，把mongodb数据库文件目录挂载到单独分区更好
mkdir -p /mongo/data创建mongodb日志文件
mkdir /var/log/mongodbtouch /var/log/mongodb/mongodb.log
4.创建mongo命令的软连接mongo bin目录下的脚本文件可以直接用了
ln -s /usr/local/mongodb/bin/* /usr/sbin
mongodb的bin下各工具的用途：mongod：数据库服务端，类似mysqld，每个实例启动一个进程，可以fork为Daemon运行mongo：客户端命令行工具，类似sqlplus/mysql，其实也是一个js解释器，支持js语法mongodump/mongorestore：将数据导入为bson格式的文件/将bson文件恢复为数据库，类似xtracbackupmongoexport/mongoimport：将collection导出为json/csv格式数据/将数据导入数据库，类似mysqldump/mysqlimportbsondump：将bson格式的文件转储为json格式的数据mongos：分片路由，如果使用了sharding功能，则应用程序连接的是mongos而不是mongodmongofiles：GridFS管理工具mongostat：实时监控工具
5启动mongodb （两种方法）方法一：直接命令行启动
mongod –-port 27017 --fork --logpath=/var/log/mongodb/mongodb.log --logappend --dbpath=/mongo/db
方法二：（配置文件启动:推荐）mkdir /usr/local/mongodb/confcd /usr/local/mongodb/confvim mongod.conf port=27017 #端口号 fork=true #以守护进程的方式运行，创建服务器进程 logpath=/var/log/mongodb/mongodb.log #日志输出文件路径 logappend=true #日志输出方式 dbpath=/mongo/db #数据库路径 shardsvr=true #设置是否分片 maxConns=600 #数据库的最大连接数 启动： mongod -f /usr/local/mongodb/conf/mongod.conf
6.验证端口27017和28017是否打开
netstat -nultp mongo命令进入mongo shell
二、mongodb主从复制配置主从复制是mongodb最常用的复制方式,这种方式很灵活.可用于备份,故障恢复,读扩展等.最基本的设置方式就是建立一个主节点和一个或多个从节点,每个从节点要知道主节点的地址.这里我们用一主一从实现mongodb的复制
1.主机分布
mongodb-master 10.48.255.244 mastermongodb-slave 10.48.255.243 slave
2.把以上安装过程应用于mongodb这两个主机，配置文件稍加改动
在mongodb-master上，配置文件增加master=trueoplogSize=2048 #类似于mysql的日志滚动，单位m
在mongodb-slave上，配置文件增加：
slave=truesource=10.48.100.1:27017 #指定主mongodb serverslavedelay=10 #延迟复制，单位为秒autoresync=true #当发现从服务器的数据不是最新时，向主服务器请求同步数据
三、测试主从可用性在两主机上启动mongodb： mongod -f /usr/local/mongodb/conf/mongod.conf1.看日志信息主上日志：
# tail /var/log/mongodb/mongodb.log Thu Aug 16 17:59:44 [initandlisten] connection accepted from 10.48.255.243:38034 #1Thu Aug 16 17:59:57 [conn1] end connection 10.48.255.243:38034Thu Aug 16 18:00:08 [initandlisten] connection accepted from 10.48.255.243:38035 #2Thu Aug 16 18:00:43 [clientcursormon] mem (MB) res:30 virt:8749 mapped:4302
从上日志
# tail /var/log/mongodb/mongodb.log Thu Aug 16 18:00:28 [replslave] repl: from host:10.48.255.244:27017Thu Aug 16 18:00:28 [replslave] repl: applied 1 operationsThu Aug 16 18:00:28 [replslave] repl: syncedTo: Aug 16 18:00:17 502d3531:1Thu Aug 16 18:00:28 [replslave] waiting until: 1345140038 to continueThu Aug 16 18:00:28 [replslave] repl: sleep 10 sec before next passThu Aug 16 18:00:38 [replslave] repl: from host:10.48.255.244:27017Thu Aug 16 18:00:38 [replslave] repl: applied 1 operationsThu Aug 16 18:00:38 [replslave] repl: syncedTo: Aug 16 18:00:27 502d353b:1Thu Aug 16 18:00:38 [replslave] waiting until: 1345140048 to continueThu Aug 16 18:00:38 [replslave] repl: sleep 10 sec before next pass
由上述信息知道主从可以建立通信了 2.下面我们在主上创建数据库，并插入集合文档，看其是否同步在主服务器上：
# mongoMongoDB shell version: 2.0.7connecting to: test> show dbslocal 4.201171875GB> use xinswitched to db xin> db.test.save({title:"just test"})> db.test.find(){ "_id" : ObjectId("502d3643c5664ca66103a7cf"), "title" : "just test" }> show dbslocal 4.201171875GBxin 0.203125GB> 注：xin是数据库名，test是集合名，{title:"just test"}是文档
mongodb中使用use即可创建一个数据库当然也可以切换数据库，和mysql有很大区别吧 让我们来看看日志吧主 server上的日志：Thu Aug 16 18:04:51 [FileAllocator] creating directory /mongo/db/_tmpThu Aug 16 18:04:51 [FileAllocator] done allocating datafile /mongo/db/xin.ns, size: 16MB, took 0.001 secsThu Aug 16 18:04:53 [FileAllocator] allocating new datafile /mongo/db/xin.0, filling with zeroes...Thu Aug 16 18:04:53 [FileAllocator] done allocating datafile /mongo/db/xin.0, size: 64MB, took 0.034 secsThu Aug 16 18:04:53 [FileAllocator] allocating new datafile /mongo/db/xin.1, filling with zeroes...Thu Aug 16 18:04:53 [FileAllocator] done allocating datafile /mongo/db/xin.1, size: 128MB, took 0.04 secsThu Aug 16 18:04:53 [conn3] build index xin.test { _id: 1 }Thu Aug 16 18:04:53 [conn3] build index done 0 records 0.012 secsThu Aug 16 18:04:53 [conn3] insert xin.test 2892msThu Aug 16 18:05:07 [initandlisten] connection accepted from 10.48.255.243:60173 #4Thu Aug 16 18:05:08 [conn4] end connection 10.48.255.243:60173 从 server上的日志：
Thu Aug 16 18:05:04 [replslave] repl: from host:10.48.255.244:27017Thu Aug 16 18:05:04 [replslave] resync: dropping database xinThu Aug 16 18:05:04 [replslave] removeJournalFilesThu Aug 16 18:05:04 [replslave] resync: cloning database xin to get an initial copyThu Aug 16 18:05:04 [FileAllocator] allocating new datafile /mongo/db/xin.ns, filling with zeroes...Thu Aug 16 18:05:04 [FileAllocator] creating directory /mongo/db/_tmpThu Aug 16 18:05:04 [FileAllocator] done allocating datafile /mongo/db/xin.ns, size: 16MB, took 0 secsThu Aug 16 18:05:04 [FileAllocator] allocating new datafile /mongo/db/xin.0, filling with zeroes...Thu Aug 16 18:05:04 [FileAllocator] done allocating datafile /mongo/db/xin.0, size: 64MB, took 0 secsThu Aug 16 18:05:04 [FileAllocator] allocating new datafile /mongo/db/xin.1, filling with zeroes...Thu Aug 16 18:05:04 [FileAllocator] done allocating datafile /mongo/db/xin.1, size: 128MB, took 0.001 secsThu Aug 16 18:05:04 [replslave] build index xin.test { _id: 1 }Thu Aug 16 18:05:04 [replslave] build index done 1 records 0 secsThu Aug 16 18:05:04 [replslave] resync: done with initial clone for db: xinThu Aug 16 18:05:04 [replslave] repl: applied 1 operations 由上述日志可以看出xin数据库已经同步到从 server上了 3.我们进入从 server 的mongodb shell,确认一下
# mongoMongoDB shell version: 2.0.7connecting to: test> show dbslocal 0.203125GBxin 0.203125GB>> use xinswitched to db xin> db.test.find(){ "_id" : ObjectId("502d3643c5664ca66103a7cf"), "title" : "just test" } 我们创建的数据库数据并不多，为什么会有0.2G呢，这是因为mongodb预分配数据库的空间，这使下次向数据库中插入数据更快了 4.在 从server 上查看Collection(集合)状态
> db.printCollectionStats()system.indexes{"ns" : "xin.system.indexes","count" : 1,"size" : 64,"avgObjSize" : 64,"storageSize" : 4096,"numExtents" : 1,"nindexes" : 0,"lastExtentSize" : 4096,"paddingFactor" : 1,"flags" : 0,"totalIndexSize" : 0,"indexSizes" : {},"ok" : 1}---test{"ns" : "xin.test","count" : 1,"size" : 44,"avgObjSize" : 44,"storageSize" : 8192,"numExtents" : 1,"nindexes" : 1,"lastExtentSize" : 8192,"paddingFactor" : 1,"flags" : 1,"totalIndexSize" : 8176,"indexSizes" : {"_id_" : 8176},"ok" : 1}--- 在 从server 上查看主从复制的状态
> db.printReplicationInfo()this is a slave, printing slave replication info.source: 10.48.255.244:27017syncedTo: Thu Aug 16 2012 18:33:27 GMT+0000 (UTC)= 18 secs ago (0.01hrs)> > db.printSlaveReplicationInfo()source: 10.48.255.244:27017syncedTo: Thu Aug 16 2012 18:34:37 GMT+0000 (UTC)= 20 secs ago (0.01hrs)
ok,mongodb的主从复制搞定了!