4-5 TB, is pretty trivial for a year's worth of data. Any decently architected cube set (SSAS) should be just fine. I'm alwasy skeptical of the latest buzz word, so I'd be curious to know what that contractor means by Sharding. As far as I know SQL Server only offer partitioning, currently. And SQL Azure, offers sharding, but, I think, that is managed at the back-end and is not user controllable.