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.tgz

2.解压

tar xvf mongodb-linux-x86_64-2.0.7.tgz

mkdir /usr/local/mongodb

mv 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/mongodb

touch /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xtracbackup

mongoexport/mongoimport：将collection导出为json/csv格式数据/将数据导入数据库，类似mysqldump/mysqlimport

bsondump：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mongod

mongofiles：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/conf

cd /usr/local/mongodb/conf

vim 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

mongodb-master 10.48.255.244 master

mongodb-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=true

oplogSize=2048 #类似于mysql的日志滚动，单位m

在mongodb-slave上，配置文件增加：

slave=true

source=10.48.100.1:27017 #指定主mongodb server

slavedelay=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.conf

1.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 #1

Thu Aug 16 17:59:57 [conn1] end connection 10.48.255.243:38034

Thu Aug 16 18:00:08 [initandlisten] connection accepted from 10.48.255.243:38035 #2

Thu 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:10.48.255.244:27017

Thu Aug 16 18:00:28 [replslave] repl: applied 1 operations

Thu Aug 16 18:00:28 [replslave] repl: syncedTo: Aug 16 18:00:17 502d3531:1

Thu Aug 16 18:00:28 [replslave] waiting until: 1345140038 to continue

Thu Aug 16 18:00:28 [replslave] repl: sleep 10 sec before next pass

Thu Aug 16 18:00:38 [replslave] repl: from host:10.48.255.244:27017

Thu Aug 16 18:00:38 [replslave] repl: applied 1 operations

Thu Aug 16 18:00:38 [replslave] repl: syncedTo: Aug 16 18:00:27 502d353b:1

Thu Aug 16 18:00:38 [replslave] waiting until: 1345140048 to continue

Thu 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：

# mongo

MongoDB shell version: 2.0.7

connecting to: test

> show dbs

local 4.201171875GB

> use xin

switched to db xin

> db.test.save({title:"just test"})

> db.test.find()

{ "_id" : ObjectId("502d3643c5664ca66103a7cf"), "title" : "just test" }

> show dbs

local 4.201171875GB

xin 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/_tmp

Thu Aug 16 18:04:51 [FileAllocator] done allocating datafile /mongo/db/xin.ns, size: 16MB, took 0.001 secs

Thu 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 secs

Thu 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 secs

Thu 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 secs

Thu Aug 16 18:04:53 [conn3] insert xin.test 2892ms

Thu Aug 16 18:05:07 [initandlisten] connection accepted from 10.48.255.243:60173 #4

Thu 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:10.48.255.244:27017

Thu Aug 16 18:05:04 [replslave] resync: dropping database xin

Thu Aug 16 18:05:04 [replslave] removeJournalFiles

Thu Aug 16 18:05:04 [replslave] resync: cloning database xin to get an initial copy

Thu 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/_tmp

Thu Aug 16 18:05:04 [FileAllocator] done allocating datafile /mongo/db/xin.ns, size: 16MB, took 0 secs

Thu 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 secs

Thu 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 secs

Thu 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 secs

Thu Aug 16 18:05:04 [replslave] resync: done with initial clone for db: xin

Thu 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

# mongo

MongoDB shell version: 2.0.7

connecting to: test

> show dbs

local 0.203125GB

xin 0.203125GB

>

> use xin

switched 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: 10.48.255.244:27017

syncedTo: Thu Aug 16 2012 18:33:27 GMT+0000 (UTC)

= 18 secs ago (0.01hrs)

>

> db.printSlaveReplicationInfo()

source: 10.48.255.244:27017

syncedTo: 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!