In late 2015, Microsoft announced unlimited storage for OneDrive for Business, and the plans have now been laid out. Microsoft Office 365 customers who have Enterprise E3, E4 or E5 plans, will get the unlimited storage. Education, OneDrive for Business plan 2, SharePoint Online plan 2, and Government E3, E4, and E5 plans will also get the unlimited storage.
Businesses wishing to take advantage of this need to be subscribed to the plans above, and have 5 subscriptions or more. The unlimited storage started rolling out in December 2015, and is expected to be across all tenants by March 2016.
You may want to have a look at the new OneDrive for Business sync tools here.