重装系统后，把原mongoDB安装目录和原mongoDB的data目录拷贝到新硬盘的D盘上。
恢复的方法如下。
1、D:\Mongodb里放着mongod.cfg和data
C:\Users\Administrator>dir D:\Mongodb
驱动器 D 中的卷没有标签。
卷的序列号是 A48D-4D74
D:\Mongodb 的目录
2017/05/06 21:48 <DIR> .
2017/05/06 21:48 <DIR> ..
2017/05/06 21:48 <DIR> data
2017/03/19 19:57 110 mongod.cfg
1 个文件 110 字节
3 个目录 1,017,095,073,792 可用字节
其中mongod.cfg中内容如下：
systemLog:
destination: file
path: D:\Mongodb\data\log\mongod.log
storage:
dbPath: D:\Mongodb\data\db
2、打开cmd。执行
C:\Users\Administrator>"D:\Program Files\mongodb-win32-i386-3.0.7\bin\mongod.exe
" --config D:\Mongodb\mongod.cfg --install
2017-05-07T15:07:18.761+0800 I CONTROL
2017-05-07T15:07:18.763+0800 W CONTROL 32-bit servers don't have journaling ena
bled by default. Please use --journal if you want durability.
2017-05-07T15:07:18.763+0800 I CONTROL
2017-05-07T15:07:18.766+0800 I CONTROL log file "D:\Mongodb\data\log\mongod.log
" exists; moved to "D:\Mongodb\data\log\mongod.log.2017-05-07T07-07-18".
C:\Users\Administrator>net start MongoDB
MongoDB 服务已经启动成功。
这个时候，在系统里可以看到mongodb的服务了。
3、测试下原来的数据还在不在。打开pycharm中mongodb的mongodb控件。做连接测试，发现连接超时。回到服务里，发现mongodb状态是停止的。于是打开日志文件D:\Mongodb\data\log，有如下的报错
2017-05-07T15:23:33.144+0800 I CONTROL Hotfix KB2731284 or later update is not installed, will zero-out data files
2017-05-07T15:23:33.147+0800 I CONTROL Trying to start Windows service 'MongoDB'
2017-05-07T15:23:33.148+0800 I STORAGE Service running
2017-05-07T15:23:33.149+0800 W - [initandlisten] Detected unclean shutdown - D:\Mongodb\data\db\mongod.lock is not empty.
2017-05-07T15:23:33.163+0800 I STORAGE [initandlisten] **************
Unclean shutdown detected.
Please visit http://dochub.mongodb.org/core/repair for recovery instructions.
*************
2017-05-07T15:23:33.166+0800 I STORAGE [initandlisten] exception in initAndListen: 12596 old lock file, terminating
2017-05-07T15:23:33.166+0800 I CONTROL [serviceStopWorker] dbexit: rc: 49
查询了下，于是进入D:\Program Files\mongodb-win32-i386-3.0.7\bin目录下，执行mongodb-win32-i386-3.0.7\bin>mongod --repair --dbpath D:\Mongodb\data\db
D:\Program Files\mongodb-win32-i386-3.0.7\bin>mongod --repair --dbpath D:\Mongodb\data\db
2017-05-07T15:25:34.931+0800 I CONTROL
2017-05-07T15:25:34.932+0800 W CONTROL 32-bit servers don't have journaling ena
bled by default. Please use --journal if you want durability.
2017-05-07T15:25:34.934+0800 I CONTROL
2017-05-07T15:25:34.940+0800 I CONTROL Hotfix KB2731284 or later update is not....
再重新net start MongoDB。进入服务，发现状态是已启动，再做连接测试，OK。查询数据，也还在！
4、总结下，要做数据恢复。mongodb 32位可以直接在64位windows下用，而且拷过来就行，不用安装。