来源：http://francs3.blog.163.com/blog/static/405767272012101923734903/

和之前介绍的 mongoexport 的数据导出工具不同， mongodump 是将数据以二进制形式导出，
而 mongoexport 导出的数据格式为 csv 或 json 格式； mongodump 可以导出一个数据库，或者
整个 MongoDB 服务上的所有数据库，因此 mongodump 是更大范围的备份工具。

一 备份一个数据库

[mongo@redhatB tf]$ mongodump -h 127.0.0.1 -d skytf -o skytf.dmp connected to: 127.0.0.1 Sat Nov 17 17:11:19 DATABASE: skytf      to     skytf.dmp/skytf Sat Nov 17 17:11:19     skytf.test_1 to skytf.dmp/skytf/test_1.bson Sat Nov 17 17:11:19 doing snapshot query Sat Nov 17 17:11:19              1 objects Sat Nov 17 17:11:19     Metadata for skytf.test_1 to skytf.dmp/skytf/test_1.metadata.json Sat Nov 17 17:11:19     skytf.things to skytf.dmp/skytf/things.bson Sat Nov 17 17:11:19 doing snapshot query Sat Nov 17 17:11:19              30 objects Sat Nov 17 17:11:19     Metadata for skytf.things to skytf.dmp/skytf/things.metadata.json Sat Nov 17 17:11:19     skytf.things_1 to skytf.dmp/skytf/things_1.bson Sat Nov 17 17:11:19 doing snapshot query Sat Nov 17 17:11:19              30 objects Sat Nov 17 17:11:19     Metadata for skytf.things_1 to skytf.dmp/skytf/things_1.metadata.json Sat Nov 17 17:11:19     skytf.test_2 to skytf.dmp/skytf/test_2.bson Sat Nov 17 17:11:19 doing snapshot query Sat Nov 17 17:11:19              4 objects Sat Nov 17 17:11:19     Metadata for skytf.test_2 to skytf.dmp/skytf/test_2.metadata.json

   备注：从日志看出，mongodump 的结果会生成一个目录，第一层目录为数据库名，
              再下一层为每个集合对应的备份文件。

二 备份一个集合

[mongo@redhatB tf]$ mongodump -h 127.0.0.1 -d skytf -c things  -o things.dmp connected to: 127.0.0.1 Sat Nov 17 17:12:20 DATABASE: skytf      to     things.dmp/skytf Sat Nov 17 17:12:20     skytf.things to things.dmp/skytf/things.bson Sat Nov 17 17:12:20 doing snapshot query Sat Nov 17 17:12:20              30 objects Sat Nov 17 17:12:20     Metadata for skytf.things to things.dmp/skytf/things.metadata.json

     备注： mongodump 加上 -c  参数则可备份指定集合。

三 备份整个实例

[mongo@redhatB tf]$ mongodump -h 127.0.0.1 -o all.dmp connected to: 127.0.0.1 Sat Nov 17 17:17:04 all dbs Sat Nov 17 17:17:04 DATABASE: skytf      to     all.dmp/skytf Sat Nov 17 17:17:04     skytf.test_1 to all.dmp/skytf/test_1.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              1 objects Sat Nov 17 17:17:04     Metadata for skytf.test_1 to all.dmp/skytf/test_1.metadata.json Sat Nov 17 17:17:04     skytf.things to all.dmp/skytf/things.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              30 objects Sat Nov 17 17:17:04     Metadata for skytf.things to all.dmp/skytf/things.metadata.json Sat Nov 17 17:17:04     skytf.things_1 to all.dmp/skytf/things_1.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              30 objects Sat Nov 17 17:17:04     Metadata for skytf.things_1 to all.dmp/skytf/things_1.metadata.json Sat Nov 17 17:17:04     skytf.test_2 to all.dmp/skytf/test_2.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              4 objects Sat Nov 17 17:17:04     Metadata for skytf.test_2 to all.dmp/skytf/test_2.metadata.json Sat Nov 17 17:17:04 DATABASE: test       to     all.dmp/test Sat Nov 17 17:17:04     test.test_2 to all.dmp/test/test_2.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              4 objects Sat Nov 17 17:17:04     Metadata for test.test_2 to all.dmp/test/test_2.metadata.json Sat Nov 17 17:17:04     test.things to all.dmp/test/things.bson Sat Nov 17 17:17:04 doing snapshot query Sat Nov 17 17:17:04              30 objects Sat Nov 17 17:17:04     Metadata for test.things to all.dmp/test/things.metadata.json

   备注：mongodump 如果不指定 -d 参数，刚会备份整个 MongoDB 实例。

--3.1 查看目录

[mongo@redhatB tf]$ ll all.dmp/ total 8.0K drwxrwxr-x. 2 mongo mongo 4.0K Nov 17 17:17 skytf drwxrwxr-x. 2 mongo mongo 4.0K Nov 17 17:17 test

     备注：在目录 all.dmp 下产生了两个目录，目录名分别对应 MongoDB 上实例上的数据库名。
 

四 参考
http://docs.mongodb.org/manual/reference/mongodump/