mongodb的安装及主从复制

转载http://linuxme.blog.51cto.com/1850814/965184

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

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  10.48.100.1   master

mongodb-slave   10.48.100.2   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(测试时主从没同步,主从服务器配置文件中去掉这个和“shardsvr=true”就同步了,不知道是不是延迟的影响

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

local4.201171875GB

> use xin

switched to db xin

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

> db.test.find()

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

> show dbs

local4.201171875GB

xin0.203125GB

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

local0.203125GB

xin0.203125GB

>

> 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!


备注:在从库执行show dbs,报错

> show dbs

2017-07-20T09:36:57.629-0400 E QUERY    Error: listDatabases failed:{ "note" : "from execCommand", "ok" : 0, "errmsg" : "not master" }

    at Error (<anonymous>)

    at Mongo.getDBs (src/mongo/shell/mongo.js:47:15)

    at shellHelper.show (src/mongo/shell/utils.js:630:33)

    at shellHelper (src/mongo/shell/utils.js:524:36)

    at (shellhelp2):1:1 at src/mongo/shell/mongo.js:47


 解决方法:

参考:https://segmentfault.com/a/1190000002924522、

在报错的slave机器上执行 rs.slaveOk()方法即可。

> rs.slaveOk()
> show dbslocal  0.078GBtest   0.078GB
> use testswitched to db test> show collections
system.indexes
users
> db.users.find()
{ "_id" : ObjectId("55763d98db85929bb8addedf"), "username" : "lwb" }
{ "_id" : ObjectId("55764a694b24187a7a3c6693"), "username" : "mongodb master-sla