Source
r/Bitcoin•
scientastics

Why Craig Wright is wrong about future storage costs for Bitcoin

I'm sorry to have to say this, but both sides of this debate have become far too politicized and engaged in name calling. I do lean toward SegWit and smaller blocks, for various reasons, but I have also tried to understand the case for bigger blocks and have also tried to understand why some think SegWit is a problematic implementation.

As such, I have done some listening to the live feed (now recorded) of the Future of Bitcoin conference. There are some valid points made. But one claim by Craig Wright that I had to challenge is that storage will continue to double at the same speed as Bitcoin.

Moore's Law is the observation that the number of transistors on a given area have been doubling roughly every 18 months. But this rate of growth is slowing down as the cost of miniaturization, and building the factories necessary, also seems to double in a similar amount of time, among other factors.

Kryder's Law is an analogous observation that storage was doubling roughly every year (when the observation was initially made). However, the Kryder rate (of increase in storage per year) has been far slower than anticipated since about 2010. Several companies' business models have been disrupted by this change in projection to such a degree that some have gone out of business.

As just one example of the many references to this slowing rate of growth, I cite the academic paper "The Economics of Long-Term Data Storage" (available at https://lockss.org/locksswp/wp-content/uploads/2012/09/unesco2012.pdf), since Craig Wright likes economic arguments.

Moore's Law has been declared "dead" multiple times, but has almost always managed to surprise observers. Yet even transistor density growth is slowing down now.

I believe that bigger blocks are inevitable, and a modest growth in block size is not a huge threat to Bitcoin's decentralization. However, it would be foolish to base our entire scalability approach on an assumption about storage growth that increasingly looks unrealistic.

This does not even get into the rate of increase in network speeds, another scalability factor we must take into account. (See Nielsen's Law, still on track but not with as an aggressive a rate of growth as Moore's Law.)

For these and other reasons, I think it is essential to explore other ways of scaling beyond brute size. I agree that staying at just 1MB raw block size every 10 minutes may be too limiting to Bitcoin's growth, even after a temporary reprieve given by SegWit. But expecting to jump to 8MB or even 32MB and then growing with no end in sight is also dangerous.

TL; DR version: Storage growth is nowhere near fast enough to fit with Craig Wright's assumptions.

Posted Jul 5, 2017, 4:28 PM UTC · edited

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ebliever•

This sounds about right. In debating this I looked at my own systems and found that there's been only 1 doubling since about 2009, very roughly speaking.

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ray-jones•

I cite the academic paper "The Economics of Long-Term Data Storage" (available at https://lockss.org/locksswp/wp-content/uploads/2012/09/unesco2012.pdf), since Craig Wright likes economic arguments.

The examples that the authors have chosen provide reliable storage used in a random access manner. So the service provider must use some type of storage redundancy* and have enough high-speed caching, via SSDs or RAM, to allow fast random access even when the storage device is slow. Therefore prices for online storage include much more than just raw storage.

You should be able to use unreliable non-RAID storage for the blockchain, since lost data can be easily downloaded again. And most of the time your local copy of the blockchain will be sequentially written and infrequently read, so not much caching is needed. Generic discussions of storage costs do not necessarily directly apply to local blockchain storage.

*It's been informally estimated in random places on the Internet that the reliability figures Amazon publishes for S3 storage are consistent with everything being stored on three disks.

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scientasticsOP•

You have a point, but it doesn't really invalidate my argument about the growth curve. You're talking about a linear factor which may give us a few years of affordability, but it will quickly be eaten up by exponential growth on the blockchain if the pace of growth in storage does not match it.

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ray-jones•

That entire paper is suspect. If the authors overlooked such an obvious distinction as minimally-cached local unreliable storage vs heavily-cached cloud-based reliable storage, who knows what else they overlooked?

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scientasticsOP•

I don't think you got the point of my last reply. Even for the paper itself, what you are mentioning (the difference between replicated high-reliability data vs. a local single copy) is only a linear constant, and does not affect the overall conclusion or the expectation of exponential growth that has failed to materialize.

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scientasticsOP•

The fact is, several businesses built their profit model on an expectation of exponential growth in the storage sector. When this failed to materialize, they had to either exit the market or severely change their business plans. All I'm saying is that Craig Wright blithely makes the same assumption about future growth, and so his plans might need to be revised in the future.

For the record, I'm in favor of both SegWit and a modest base block size increase. I just don't think it's a great idea to try to expand the block size to the moon right away.

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