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Comment by boffinism | Hacker News Reader

> 440% cheaper than S3 per GB.

However the author thinks percentages work.... They are not right.

Driven by the fact that using comparative adjectives in this context seems to be at best confusing, I thought I'd play around with some numbers to see if I could understand what the author was trying to convey.

First, it's important to clarify why comparative adjectives don't work here. Look at the following sentence.

- A $5 cookie is worth twice as much as a $2.50 cookie

Here, we establish the baseline (the $2.50 cookie), and express how much better the $5 cookie is.

We could also say the inverse:

- A $2.50 cookie is worth half as much as a $5 cookie.

What we can't do is the following:

- A $5 cookie is double more expensive than a $2.50 cookie.

We can make a statement (the cookie is more expensive), or share the factor by establishing the baseline (twice as expensive as), but not both at the same time.

The author tries to say 440% cheaper, (not mentioning storage or transfer) and I believe their logic was something along the lines of the below:

- 440% = 440/100

- Cheaper = Reciprocal of More expensive

- 440% cheaper = 1 / (440/100) = 100/440

- S3 is very difficult to estimate a 'per GB price' because it depends on where the data is being transferred to, various pricing tiers (S3, S3 intelligent, 'Glacier', 'infrequent access', 'One Zone', first 100GB free, egress through Cloudfront, and HTTP verb specifics). Fortunately, they have an estimate calculator, which gave me 9 USD for 100GB transferred out to the internet, or 0.09USD/GB for transfer.

- Storage is a different proposition, with Amazon telling me it'll cost 2.30 USD for 100GB as long as I never look at it (ie: 0.023USD/GB)

- Backblaze is much easier to reckon with, with $0.005/GB for storage, and $0.01 for transfer.

- Therefore, for transfer Amazon's 0.09 * (100/440) = 0.02, which is MORE than Backblaze would charge me.

- For storage, Amazon's 0.023 * (100/440) is indeed 0.005.

So, Backblaze does indeed seem to be [440%, reciprocal of more expensive] as Amazon for storage cost alone.

Then again, the title of the post says "practically free" and goes on to say it's actually $5 a month, so I took the rest of the figures with a grain of salt...

B2 itself is not $5 a month. That $5 service is a separate consumer-focused "unlimited" backup service from the same company. B2 just charges for storage and transfer. Yeah, the author was rambling a bit.

B2 costs me roughly 52 cents per month to backup 250GB of data. I'd say that if you have enough income to have an internet connection and generate enough data to want a cloud backup tool, it is effectively free.

The wording is indeed confusing, but not every interpretation is wrong. They might mean 440% more efficient, i.e. 5.4x cheaper.

That's still an innumerate phrasing.

yeah pretty sure they mean 77% cheaper

It does make sense. Consider the phrase "twice as cheap"

What is 440% less than 1, then? In my book, it's -3.4.

It should be percentage points, because "100% cheaper" would already be free.

It probably means AWS is 440% more expensive.

Technically yes but no person is reading that and thinking backblaze is paying you or its free. Its a nitpick

I have always found that phrasing to be confusing. Consider the reciprocal, “half as cheap”. Should that be interpreted as… double?

Say “half the cost” or “cheaper by half”.

> Consider the reciprocal, “half as cheap”. Should that be interpreted as… double?

If the phrasing makes it clear they're talking about a higher price, then yes that's a good interpretation. You get half as good a deal.

Someone might say "half as cheap" to talk about a price drop by 50%, even though that's not really correct, but such is language.

It doesn't make sense. Consider the phrase "once as cheap". Multiply by two. That's twice as cheap. Meaningless.

Do you think "twice as expensive" is meaningless? Because by that same logic, if I start with "once as expensive" that's not a number and multiplying by two gives me a meaningless concept.

Once as expensive is a number, it's 1 x the cost. Twice as expensive is 2x the cost. Once as cheap might arguably be 1x the cost, but twice as cheap is undefined.

> Once as expensive is a number, it's 1 x the cost.

Nobody says that. If someone said "once as expensive" I'd interpret "once" as talking about time.

"Once" can be a counter but not a multiple.

It seems like we're taking at cross purposes. I'm not trying to convince you that anyone says "once as X". I'm just saying "twice as cheap" is nonsensical. Because it's a multiple of something undefined.

I've considered it, and decided that "twice as cheap" is equally poor choice of words

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