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by wtallis
3172 days ago
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The biggest lesson to take away from this is probably that they thought they knew how to test a SSD, but were quite obviously clueless: > we run a fairly comprehensive set of block-level tests using fio, consisting of both sequential and random asynchronous reads and writes straight to the disk. Then we throw a few timed runs of the venerable dd program at it. Running dd as a benchmark is a major red flag. It show that they didn't know what they were doing with fio, and didn't trust its results. They later started using IOzone and a custom-written tool to accomplish stuff they should have done with fio in their initial testing. They also did not mention pre-conditioning the drives or ensuring that their tests run long enough to reach a steady state. This is one of the most important aspects of enterprise SSD testing and they would have known that if they'd consulted any outside resources on the subject instead of making up their own testing guidelines from a position of extreme ignorance about the fundamentals of the hardware they were using and the details of their own workload. They really should stop calling any of their tests "comprehensive". |
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This is not a comprehensive guide to testing SSDs, it’s the story of what the author went through when trying to test SSDs. It’s well written and the author seemed to really engage with the topic and describe all the setbacks he had and research they did. I did not think he presented himself as an expert, just a software engineer tasked with upgrading their SSDs. And who knows, maybe this was only a 20% time project.
There are a lot of blog posts on HN that have much less actual content and where the authors have much less of a clue, yet often the response is overwhelmingly positive because someone took the time to write it up. You should really be more charitable here.
And to adress the calls for “outside experts”: If everyone called in outside experts for everything hardware (or software) related, we software engineers would never get to do anything cool or learn some new framework. We’d just be watching an outside expert do their thing. And outside “experts” are not necessarily better, often they might just sell themselves better. And who is going to check their work if the knowledge is all outsourced?
I think it’s great that the BBC lets their engineers do this and learn along the way, and a place where that is possible sounds like a nice place to work. It’s not like they had any downtime or anything because of this.