mongodump.exe備份的原理是通過一次查詢獲取當前服務器快照，并將快照寫入磁盤中，因此這種方式保存的也不是實時的，因為在獲取快照后，服務器還會有數據寫入，為了保證備份的安全，同樣我們還是可以利用fsync鎖使服務器數據暫時寫入緩存中。

高效開源數據庫(mongodb)下載地址：

備份前的檢查
> show dbs
MyDB 0.0625GB
admin (empty)
bruce 0.0625GB
local (empty)
test 0.0625GB
> use MyDB
switched to db MyDB
> db.users.find()
{ “_id” : ObjectId(“4e290aa39a1945747b28f1ee”), “a” : 1, “b” : 1 }
{ “_id” : ObjectId(“4e2cd2182a65c81f21566318”), “a” : 3, “b” : 5 }
>

整庫備份：
mongodump -h dbhost -d dbname -o dbdirectory
-h：MongDB所在服務器地址，例如：127.0.0.1，當然也可以指定端口號：127.0.0.1:27017
-d：需要備份的數據庫實例，例如：test
-o：備份的數據存放位置，例如：c:datadump，當然該目錄需要提前建立，在備份完成后，系統自動在dump目錄下建立一個test目錄，這個目錄里面存放該數據庫實例的備份數據。

mongodump的官方說明(可通過mongodump –help查看)：

options:

 –help          produce help message

 -v [ –verbose ]     be more verbose (include multiple times for more

              verbosity e.g. -vvvvv)

 –version        print the program’s version and exit

 -h [ –host ] arg    mongo host to connect to ( /s1,s2 for

              sets)

 –port arg        server port. Can also use –host hostname:port

 –ipv6          enable IPv6 support (disabled by default)

 -u [ –username ] arg  username

 -p [ –password ] arg  password

 –dbpath arg       directly access mongod database files in the given

              path, instead of connecting to a mongod server –

              needs to lock the data directory, so cannot be used

              if a mongod is currently accessing the same path

 –directoryperdb     if dbpath specified, each db is in a separate

              directory

 –journal        enable journaling

 -d [ –db ] arg     database to use

 -c [ –collection ] arg collection to use (some commands)

 -o [ –out ] arg (=dump) output directory or “-” for stdout

 -q [ –query ] arg    json query

 –oplog         Use oplog for point-in-time snapshotting

 –repair         try to recover a crashed database

 –forceTableScan     force a table scan (do not use $snapshot)

整庫恢復：
mongorestore -h dbhost -d dbname –directoryperdb dbdirectory
-h：MongoDB所在服務器地址
-d：需要恢復的數據庫實例，例如：test，當然這個名稱也可以和備份時候的不一樣，比如test2
–directoryperdb：備份數據所在位置，例如：c:datadumptest，這里為什么要多加一個test，而不是備份時候的dump，讀者自己查看提示吧！
–drop：恢復的時候，先刪除當前數據，然后恢復備份的數據。就是說，恢復后，備份后添加修改的數據都會被刪除，慎用哦！

mongorestore的官方說明(可通過mongorestore –help查看)：

options:

 –help         produce help message

 -v [ –verbose ]    be more verbose (include multiple times for more

             verbosity e.g. -vvvvv)

 –version        print the program’s version and exit

 -h [ –host ] arg    mongo host to connect to ( /s1,s2 for sets)

 –port arg       server port. Can also use –host hostname:port

 –ipv6         enable IPv6 support (disabled by default)

 -u [ –username ] arg  username

 -p [ –password ] arg  password

 –dbpath arg      directly access mongod database files in the given

             path, instead of connecting to a mongod server –

             needs to lock the data directory, so cannot be used

             if a mongod is currently accessing the same path

 –directoryperdb    if dbpath specified, each db is in a separate

             directory

 –journal        enable journaling

 -d [ –db ] arg     database to use

 -c [ –collection ] arg collection to use (some commands)

 –objcheck       validate object before inserting

 –filter arg      filter to apply before inserting

 –drop         drop each collection before import

 –oplogReplay      replay oplog for point-in-time restore

 –oplogLimit arg    exclude oplog entries newer than provided timestamp

             (epoch[:ordinal])

 –keepIndexVersion   don’t upgrade indexes to newest version

 –noOptionsRestore   don’t restore collection options

 –noIndexRestore    don’t restore indexes

 –w arg (=1)      minimum number of replicas per write

單個collection備份：
mongoexport -h dbhost -d dbname -c collectionname -f collectionKey -o dbdirectory
-h: MongoDB所在服務器地址
-d: 需要恢復的數據庫實例
-c: 需要恢復的集合
-f: 需要導出的字段(省略為所有字段)
-o: 表示導出的文件名

mongoexport的官方說明(可通過mongoexport –help查看)：

 –help          produce help message

 -v [ –verbose ]     be more verbose (include multiple times for more

              verbosity e.g. -vvvvv)

 –version         print the program’s version and exit

 -h [ –host ] arg     mongo host to connect to ( /s1,s2 for

              sets)

 –port arg        server port. Can also use –host hostname:port

 –ipv6          enable IPv6 support (disabled by default)

 -u [ –username ] arg   username

 -p [ –password ] arg   password

 –dbpath arg       directly access mongod database files in the given

              path, instead of connecting to a mongod server –

              needs to lock the data directory, so cannot be used

              if a mongod is currently accessing the same path

 –directoryperdb     if dbpath specified, each db is in a separate

              directory

 –journal         enable journaling

 -d [ –db ] arg      database to use

 -c [ –collection ] arg  collection to use (some commands)

 -f [ –fields ] arg    comma separated list of field names e.g. -f

              name,age

 –fieldFile arg      file with fields names – 1 per line

 -q [ –query ] arg    query filter, as a JSON string

 –csv           export to csv instead of json

 -o [ –out ] arg     output file; if not specified, stdout is used

 –jsonArray        output to a json array rather than one object per

              line

 -k [ –slaveOk ] arg (=1) use secondaries for export if available, default

              true

 –forceTableScan     force a table scan (do not use $snapshot)

單個collection恢復：
mongoimport -d dbhost -c collectionname –type csv –headerline –file
-type: 指明要導入的文件格式
-headerline: 批明不導入第一行，因為第一行是列名
-file: 指明要導入的文件路徑

mongoimport的官方說明(可通過mongoimport –help查看)：

 –help         produce help message

 -v [ –verbose ]    be more verbose (include multiple times for more

             verbosity e.g. -vvvvv)

 –version        print the program’s version and exit

 -h [ –host ] arg    mongo host to connect to ( /s1,s2 for sets)

 –port arg       server port. Can also use –host hostname:port

 –ipv6         enable IPv6 support (disabled by default)

 -u [ –username ] arg  username

 -p [ –password ] arg  password

 –dbpath arg      directly access mongod database files in the given

             path, instead of connecting to a mongod server –

             needs to lock the data directory, so cannot be used

             if a mongod is currently accessing the same path

 –directoryperdb    if dbpath specified, each db is in a separate

             directory

 –journal        enable journaling

 -d [ –db ] arg     database to use

 -c [ –collection ] arg collection to use (some commands)

 -f [ –fields ] arg   comma separated list of field names e.g. -f name,age

 –fieldFile arg     file with fields names – 1 per line

 –ignoreBlanks     if given, empty fields in csv and tsv will be ignored

 –type arg       type of file to import. default: json (json,csv,tsv)

 –file arg       file to import from; if not specified stdin is used

 –drop         drop collection first

 –headerline      CSV,TSV only – use first line as headers

 –upsert        insert or update objects that already exist

 –upsertFields arg   comma-separated fields for the query part of the

             upsert. You should make sure this is indexed

 –stopOnError      stop importing at first error rather than continuing

 –jsonArray       load a json array, not one item per line. Currently

             limited to 16MB.

其他導入與導出操作：

1. mongoimport -d my_mongodb -c user user.dat

參數說明:

-d 指明使用的庫, 本例中為” my_mongodb”

-c 指明要導出的表, 本例中為”user”

可以看到導入數據的時候會隱式創建表結構

2. mongoexport -d my_mongodb -c user -o user.dat

參數說明:

-d 指明使用的庫, 本例中為” my_mongodb”

-c 指明要導出的表, 本例中為”user”

-o 指明要導出的文件名, 本例中為”user.dat”

從上面可以看到導出的方式使用的是JSON 的樣式.