Open Source Document Management System | OpenKM

Hi,
I have 2 separate open km installation. and upload different files and setting several tag , category and metadata for files.
Now we decide to have just one active OpenKm. and need to transfer all files and meta data from one installation to another one.
I can copy files using export to zip and import from zip file , but how can I do that with metadata?
If I use export / import from administration plan, does it overwrite all files and setting in another system and I lost other server data?

How can I do this migration ?

Thanks
Mehdi

Do you have the same folder names and document names in both sides ?
Give me some sample.