Our company has just faced a problem which surely someone has solved before and any advice is more than welcome.

We've got 2 separate business processes:

• offline: gathering, processing and loading large amounts of data into a mongodb server
• online: high-availability web sites that utilize the same data

Now, what is the best way to transfer data from offline to online server, assuring online's server 100% availability?
We need to do it only once a day and the most important thing is to minimize performance impact on the online's server.

Thank you for your suggestions in advance!