The Filecoin Plus data cap mechanism has no notion of the term for which data cap, and hence the network-subsidised rewards, should be granted. Thus, when we remove technical limitations on the length or extensibility of deals, the FIL+ QA power boost will be indefinite.

Is this a design feature?

• If so we can exploit it to greatly simplify implementation and solve most of the Challenges with QA Power.
• If not, we need to restrict FIL+ data cap terms before the term-less nature becomes built-in to architecture, user contracts, SP expectations etc.

Original Slack thread (PL-only).

Background

A brief overview of how the Filecoin Plus verified data program works today.

• FIL+ notaries assign data cap to verified clients. Data cap is measured in bytes and is single-use.
• Clients make deals with the built-in storage market actor. A deal specifies a term (start and end epoch).
• A verified client may indicate that a deal has verified data. In that case, when the deal is activated the corresponding data cap is consumed, and the deal’s space-time contributes to the “quality” of the sector in which it’s stored, increasing its reward.

The built-in storage market actor implements a limited storage market, and is trusted by the FIL+ system to determine deal/sector quality.

• Sectors have a maximum lifetime, and the storage market implementation prohibits deals with a term that exceeds the sector’s commitment. Thus deals have bounded terms.
• There is no mechanism to transfer a deal (and hence its data cap quality) to another sector.
• Therefore there is no mechanism to extend a deal’s term.

The duration for which a FIL+ verified deal provides boosted rewards to a storage provider is thus limited by the deal term. The maximum deal term is in turn limited by the maximum sector lifespan for which we believe SDR PoRep is secure (i.e. an accidental reason totally unrelated to FIL+ economics).

Where we’re headed

• Inability to extend a deal is a shortcoming of the built-in storage market, and a top-requested enhancement. It could be implemented by allowing the deal’s data to be moved/added to a new sector with a farther-out expiration.
• Similarly, the market’s prohibition of a deal term that exceeds the expiration of the sector into which the data is first sealed is an unfortunate limitation of a simplified implementation.
• There’s no technical reason we can’t support indefinite deal terms.