本次环境 RHEL6

学着用一下MongoDB，做个笔记：

下载&安装

预创建datadir和logdir

编辑配置文件

可以最简化的写一下配置，其他的默认

保存退出

启动mongodb

进入mongodb shell

或者不加选项直接：

MongoDB shell version: 3.2.10
connecting to: test
Server has startup warnings:
2016-10-03T12:38:14.769+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2016-10-03T12:38:14.769+0800 I CONTROL [initandlisten]
2016-10-03T12:38:14.769+0800 I CONTROL [initandlisten]
2016-10-03T12:38:14.769+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2016-10-03T12:38:14.769+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2016-10-03T12:38:14.774+0800 I CONTROL [initandlisten]
2016-10-03T12:38:14.774+0800 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2016-10-03T12:38:14.774+0800 I CONTROL [initandlisten] ** We suggest setting it to 'never'
2016-10-03T12:38:14.774+0800 I CONTROL [initandlisten]
>

这三个wanring，后两个可以通过修改如下文件，来关闭transparent_hugepage

但这样重启会被重置成always，可以写个脚本或者放入/etc/rc.local中

关闭hugepage之后，重启mongd，进入mongo shell则该warning消失：

shell> mongo
MongoDB shell version: 3.2.10
connecting to: test
Server has startup warnings:
2016-10-12T05:31:46.933+0800 I CONTROL [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2016-10-12T05:31:46.933+0800 I CONTROL [initandlisten]
>
>

还剩一个warning则很明显，不建议通过root用户来启动mongod。
如果不想让warning再显示，可以打开quiet选项，比如添加到配置文件中：quiet=true
或者

通过help便可获取常用mongo shell语法：

> help
db.help() help on db methods
db.mycoll.help() help on collection methods
sh.help() sharding helpers
rs.help() replica set helpers
help admin administrative help
help connect connecting to a db help
help keys key shortcuts
help misc misc things to know
help mr mapreduce
show dbs show database names
show collections show collections in current database
show users show users in current database
show profile show most recent system.profile entries with time >= 1ms
show logs show the accessible logger names
show log [name] prints out the last segment of log in memory, 'global' is default
use <db_name> set current database
db.foo.find() list objects in collection foo
db.foo.find( { a : 1 } ) list objects in foo where a == 1
it result of the last line evaluated; use to further iterate
DBQuery.shellBatchSize = x set default number of items to display on shell
exit quit the mongo shell

比如查怎么关闭mongod：
先查db相关的帮助：

> db.help()
………………
db.shutdownServer()
………………
> db.shutdownServer()
server should be down...
2016-10-13T17:58:49.544+0800 I NETWORK [thread1] trying reconnect to 127.0.0.1:27017 (127.0.0.1) failed
2016-10-13T17:58:49.547+0800 I NETWORK [thread1] Socket recv() errno:104 Connection reset by peer 127.0.0.1:27017
2016-10-13T17:58:49.547+0800 I NETWORK [thread1] SocketException: remote: (NONE):0 error: 9001 socket exception [RECV_ERROR] server [127.0.0.1:27017]
2016-10-13T17:58:49.547+0800 I NETWORK [thread1] reconnect 127.0.0.1:27017 (127.0.0.1) failed failed
>

这样，mongod就已经被关闭了。

ITPub博客

【MongoDB】 MongoDB 3.2.x 安装实践