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Comment by system2 | Hacker News Reader

Why wouldn't backblaze use only HGST then? What's the purpose of buying seagates which was the most unreliable hard drives from 15-20 years ago and their stats show higher failure rates. (Still I don't buy them because of the bad taste left.)

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Yev from Backblaze here -> Some of the responses down below are correct - it really does come down to price. We run a fairly lean ship and so the price per gigabyte is weighed pretty heavily when we make our purchasing decisions. We have a post where we go into the cost of hard drives over time, it's about 3 years old now, but still a good read -> https://www.backblaze.com/blog/hard-drive-cost-per-gigabyte/.

Do you have an algorithm of sorts that takes into account price and historical failure rate by drive model and gives you an easy "yea or nay" for purchase decisions? Seems like you might be able to automate drive purchases with such a system (similar to limit orders on financial securities).

I was wondering this as well, it seems pretty easy to write.

Also, if you don't use one, please elaborate if you can why the obvious MTBF delta projection idea is bunk. I'm sure your talented team has thoroughly thought through all of this

Yev here -> It's less of an algorithm and more of a purchasing department with lots of spreadsheets that tie into the AFR data as a data point - but yes, it's possible we could automate it, but there's some factors that our supply-chain team would need to be involved in anyway (like vendor diversity, no large batches of single drives etc...) that make outputting that algorithm a bit harder.

I would think you'd also want to be hedging your bets a bit against some kind of catastrophic bug. Flexibility in your supply lines has also got to be a big plus (and help smooth sailing with various disasters)

Yev here -> Yes we want to mitigate large batch failures by adding some drive/vendor diversification, that's definitely part of the equation!

I think this comes down to price. They are constantly buying drives and to avoid supply issues, it is acceptable to have a hard drive that fails to a certain degree, if the price is balanced.

It would be interesting if these reports included prices, but that might be a problem for Backblaze to reveal so much about their business operational costs.

Cost and availability, especially at the higher capacities. Note that HGST was bought out by WD in 2012, and WD started sunsetting the HGST brand in 2018.

Presumably cost and availability. I remember reading at one point they were driving from store to store buying every drive they could find.

That was during the flooding in Thailand that took out a huge chunk of hard drive manufacturing capacity. Electronics stores started putting quotas on purchases, so BB offered a bounty to friends and family who would bring in hard drives.

They had a disassembly line gutting external hard drive enclosures for the hard drives, too. One of the drives in my array was acquired via a similar process.

You should read the whole story. I should probably read it again myself.

https://www.backblaze.com/blog/backblaze_drive_farming/

If you have a system that can efficiently deal with a drive dying without losing data then it makes sense to weight availability and cost higher over reliability.

For home users a dead or dying drive is such a headache that it's usually worth spending the extra bucks on something that is less likely to fail on you.

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