So I just checked my onedrive and while I don't have any DNGs/PSDs over 100mb I do have some TIFFs over 100M and they don't show a preview. I'm not an expert on file types and what they can and can't do but I think it's probably a limitation of the cloud service that it's not showing a preview. That said I have videos in the multiple Gig size on Onedrive and I can see a screenshot preview so it may have something to do with limitations of the files as well. All that said I wouldn't count on OneDrive as anything more than 1 leg in a backup plan. It would be somewhat painful to use in a live workflow IMO.
I can share that I have my all my data on my local drive redirected to a local OneDrive folder so that it automatically syncs to Onedrive in the background. This isn't my primary back up though, it's a secondary failsafe. My primary backup is a direct attached 5 bay 12 TB Drobo NAS. Not cheap but it's super fast with USB3 connection (thunderbolt for Mac). I have it set up so that it can have 2 of the 5 drives fail before any data loss. (I've already lost one drive and it worked flawlessly by mirroring data to the working drives giving me time to replace the failed drive). If you have tons of photos that you can't risk losing it's worth investing $ in a backup strategy and I believe any photographer who would lose their mind over data lose needs a NAS as part of their workflow or at a minimum multiple external drives.
In my workflow I have everything backing up to that local Drobo for speed and I do a secondary backup to Onedrive as a failsafe in the event something really goes wrong with the Drobo. I also as part of my workflow final steps I export my processed "favorite" Lightroom files to folders in Onedrive via the Lightroom Onedrive plugin. In this workflow I save Large JPGs for sharing. I don't do a ton of TIFFs or large files as I really don't print much. I've also been experimenting with the Lightroom Mobile sync as well, although I don't really think of that as backup.
In any case if you have the means I'd recommend some sort of tiered backup/workflow that doesn't rely on any one point of failure. I personally believe due to files sizes in digital, local backup is a must. Cloud sync alone in my opinion is just too slow and risky as the only option. If you lose something while in the middle of your workflow, it's unlikely it would have all synced to the cloud with the exception of smaller jpegs. George Lepp has a really good tip on backup workflow strategies in Outdoor Photographer that's worth a read (I can't remember which month but it was in the last year). Granted he's got the cash to do some expensive equipment, but the philosophy is Memory cards=> import to local drive=>simultaneously backup to external drives (duplicating to multiple drives preferred). He doesn't use Cloud that I'm aware of but I personally think it can be there as a part of the backup strategy, just not a primary one.
Side note: While I am a fan of Onedrive I may go back to Carbonite as my cloud backup as they provide both local drive backup and external drive backup support as well as Disk image backup, top tiers include disk shipping for recovery. Also they don't charge incremental for storage at any tier. personal accounts are unlimited. Onedrive deal is nice with 1TB of storage included with O365 home subscription, but I'm already beyond 1TB so it's going to keep adding up, $40 for every extra 1TB of storage, which isn't bad but there are cheaper options.