Unlike Microsoft Word and PowerPoint, OneNote stores version information within the file itself. For this reason, administrators should follow these recommended practices when storing OneNote notebooks in a SharePoint Server document library: Don't enable minor versioning. This's the default setting in SharePoint Server 2010. If major versioning is enabled, set a reasonable maximum number of versions to store. By default, major versioning isn't enabled in SharePoint Server 2010.
Here're few links for all of SharePoint Server 2010 admins & deployment folks:
- Co-authoring overview
- Configure versioning for co-authoring
- Configure the co-authoring versioning period
- Configure the maximum number of co-authoring authors
- Disable co-authoring