If you are backing up more than 1,000 users or large SharePoint Sites in Office 365 with Keepit, we recommend you create three separate connectors: one for Exchange data, one for OneDrive data, and one for Groups & Teams and SharePoint data. 

This will ensure a faster initial backup speed and a higher performing subfolder search.

You can use the same Microsoft Global administrator account for each connector. See also: Preparing your Office 365 account

For details on how to add a new connector, see: How to add a Cloud Connector for Office 365

For details on how to configure your connector, see: How to configure your backup

When you are configuring your connector for Exchange data, select Calendar, Contacts, Mail, and Tasks. You can also include Public Folders with your Exchange data.