I have over 100 GB of unused disk usage (and just 7GB used) in my time series collection that isn’t being reclaimed. I am unable to compact it. When I try, I receive the error: MongoServerError: can't compact a view
I think you are correct. Currently we don’t have an easy way to reclaim unused space in a time series collection. I opened SERVER-70679 to investigate further options.
In the meantime, I can suggest a couple of workarounds for this: