storage:

   engine:　wiredTiger
   wireTiger:
       [存储引擎的参数设置]

storage:
   joural:
      enabled:　true    #启用journal日志，false为关闭
   engine:  wiredTiger  #指定存储引擎 
   wiredTiger:
      cacheSizeGB: 8    #来指定mongodb使用内存的多少-8G
      engineConfig:     #存储引擎的配置
         journalCompressor:  snappy        #指定journal日志的压缩方式
      indexConfig:                         #索引配置 
         prefixCompression:  true          #前缀压缩开启    
      collectionConfig:
         blockCompressor: snappy           #指定集合的压缩方式 

db.runCommand ( { compact: '<collection>' } )
#在执行compact命令时，MongoDB会对当前的database加锁，阻塞其他操作。在compact命令执行完成之后，mongod会重建集合的所有索引

systemLog:

  destination: file

  logAppend: true

  path: /data/mongod/log/mongod.log

storage:

  engine: "mmapv1"

  dbPath: /data/db

  journal:

    enabled: true

processManagement:

  fork: true  # fork and run in background

  pidFilePath: /var/run/mongodb/mongod.pid  # location of pidfile

# network interfaces

net:

  port:

  bindIp: 

mmapv1的配置

#数据大小如下

> show dbs;

admin  .078GB

local  .078GB

mydb   .453GB

[root@test2 data]# mkdir db_back          #创建备份目录

[root@test2 bin]# ./mongodump -o /data/db_back/       #备份数据

--09T17::54.684+    writing admin.system.indexes to

--09T17::54.685+    done dumping admin.system.indexes ( documents)

--09T17::54.685+    writing admin.system.version to

--09T17::54.686+    done dumping admin.system.version ( document)

--09T17::54.686+    writing mydb.test to

--09T17::57.676+    [###############.........]  mydb.test  /  (63.6%)

--09T17::58.632+    [########################]  mydb.test  /  (100.0%)

--09T17::58.632+    done dumping mydb.test ( documents)

[root@test2 bin]# 

kill `netstat -lntp |grep mongod | awk '{print $NF}' | cut -d "/" -f1`

storage:

  engine: wiredTiger

  wiredTiger:

    engineConfig:

      cacheSizeGB:

      journalCompressor: none

    collectionConfig:

      blockCompressor: none

    indexConfig

      prefixCompression: false

[root@test2 data]# mv db db_mmapv1

[root@test2 data]# mkdir db             #然后再重新创建一个db目录

[root@test2 bin]# ./mongod -f ../conf/mongod.conf

about to fork child process, waiting until server is ready for connections.

forked process:

child process started successfully, parent exiting

[root@test2 bin]# 

[root@test2 bin]# ./mongorestore --dir=/data/db_back/                    #导入数据

--09T17::10.586+    preparing collections to restore from

--09T17::10.599+    reading metadata for mydb.test from /data/db_back/mydb/test.metadata.json

--09T17::10.646+    restoring mydb.test from /data/db_back/mydb/test.bson

--09T17::13.546+    [########................]  mydb.test  .1MB/.4MB  (37.0%)

--09T17::16.546+    [##################......]  mydb.test  .7MB/.4MB  (78.5%)

--09T17::18.354+    [########################]  mydb.test  .4MB/.4MB  (100.0%)

--09T17::18.354+    no indexes to restore

--09T17::18.354+    finished restoring mydb.test ( documents)

--09T17::18.354+    done

[root@test2 bin]# ./mongo                                                #查看数据

MongoDB shell version v3.4.2

connecting to: mongodb://127.0.0.1:27017

MongoDB server version: 3.4.

Server has startup warnings:

--09T17::26.586+ I STORAGE  [initandlisten]

--09T17::26.586+ I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine

--09T17::26.586+ I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem

--09T17::26.688+ I CONTROL  [initandlisten]

--09T17::26.688+ I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.

--09T17::26.688+ I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.

--09T17::26.688+ I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.

--09T17::26.688+ I CONTROL  [initandlisten]

> show dbs

admin  .000GB

local  .000GB

mydb   .077GB                               #数据占有空间明显变小了

[root@test2 db]# pwd

/data/db

[root@test2 db]# ls                               #当前正在使用的wiredTiger存储引擎

collection--.wt  diagnostic.data                 index--.wt  _mdb_catalog.wt  storage.bson      WiredTiger.lock

collection--.wt  index--.wt  index--.wt  mongod.lock      WiredTiger        WiredTiger.turtle

collection--.wt  index--.wt  journal                         sizeStorer.wt    WiredTigerLAS.wt  WiredTiger.wt

[root@test2 db]# ls ../db_mmapv1/                 #之前备份的mmapv1存储引擎的目录

admin.  admin.ns  diagnostic.data  journal  local.  local.ns  mongod.lock  mydb.  mydb.  mydb.  mydb.ns  storage.bson  _tmp

[root@test2 db]#