It simply lets you choose wether the quota thresholds are applied against the file sizes as the user sees them (Bytes written to files) or against the space the files occupy on the drives, i.e. file sizes + redundancy (according to protection +2:1 and cluster size).
Community,   what exactly does this cover under SmartQuotas: Include Data-Protection Overhead?  Protection is currently set to +2:1.  I mean the box for "Include Snapshot Data" is pretty self explanatory, but what other behind the scene things is "Include Data-Protection Overhead" is being accounted for?   Thank you,
SmartQuotas - Include Data-Protection Overhead