I have 3.2.3 server running wiredtiger. The stats output does not seem reasonable.

I would expect Storage size ~= datasize + indexsize

But in this case it seems to be way off.

db.stats();

{ "db" : "xxx", "collections" : 9, "objects" : 202860, "avgObjSize" : 13789.263595583161, "dataSize" : 2797290013, "storageSize" : 10694090752, "numExtents" : 0, "indexes" : 17, "indexSize" : 18022400, "ok" : 1 }