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Testing disks: Lessons from our odyssey selecting replacement SSDs

bbc.co.uk

71–78 of 78 posts

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#71
post #32

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 th…

I think you just expected to much from this article.

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.

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#72
post #32

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 th…

I think you just expected to much from this article. 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. A…

> And to adress the calls for “outside experts”:

You completely misinterpreted (and misquoted) me on that one. I wasn't implying that they should hire a consultant for this kind of thing, but they should at least have bothered to read anything about the methodology used by SSD reviewers or the industry standard storage testing methodology freely published by organizations like SNIA. It's clear the BBC guys didn't even spend an afternoon trying to read up on how to evaluate SSD performance; they just jumped in and started re-inventing the wheel, hitting all the foreseeable problems along the way. It looks like they now have a clue and have learned a lot from the process, but this is not how you should handle this kind of upgrade.

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#73

Earlier quoted context omitted.

> like Google -> to google Hang on! Surely, "to google" refers to performing a search specifically with Google, right?

Not a chance. To google means "to search online [using a search engine]". Have you never witnessed someone googling something using Bing?

I have never witnessed anyone using Bing at all! My father used DuckDuckGo once, although he wasn't aware of it.

In any case, if I say "to google", I mean "search using Google". I try not to say it, though, because I think it sounds silly to use product names like that.

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#74
post #72

Earlier quoted context omitted.

I think you just expected to much from this article. 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. A…

> And to adress the calls for “outside experts”: You completely misinterpreted (and misquoted) me on that one. I wasn't implying that they should hire a consultant for this kind of thing, but they should at least have bothered to read anything about the methodology used by SSD reviewers or the industry standard storage testing methodology freely published by organizations like SNIA. It's clear the BBC guys didn't eve…

EDIT: no need to downvote wtallis, he has a valid point!

Sorry I misread and misunderstood that, I did not mean to misquote.

What you’re saying is of course absolutely true, they should have done much more research at the beginning.

However, at the start of a seemingly easy task, research may not be first thing to spring to mind (although it should be).

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#75

Earlier quoted context omitted.

The BBC has a very strong product prominence policy[0] (i.e. avoid naming brands when possible), being government funded is a large driver of this policy. [0] http://www.bbc.co.uk/editorialguidelines/guidelines/editoria... EDIT: fixed policy name and added link

It's a shame this is so selectively applied. See, for example: - The constant mention of speaking to people 'over Skype' on the News - Publicization of Twitter hashtags on Questiontime and other programs - Hours worth of Top Gear footage (and the entire Arctic Special) that were effectively Toyota Hilux advertisements

I mean the hashtags have no real comparison, but those other two are a bit shady.

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#76
post #47
post #43

Earlier quoted context omitted.

It's not just a matter of how many bytes are being written; desktop workloads rarely need to do synchronous writes.

There are a lot of desktop applications that does synchronous all the time. Chrome, Firefox and Spotify are a few examples as they use SQLite which does fsync() system call. But yeah, you will be fine even with a spinning hard drive. My point is, what use case is there for paying a premium for the Samsung NVMe's when you would be just fine with a cheaper model.

I've had about 20 spinning drives fail on me in the past 25 years or so. The more I can keep spinning drives out of my life, the happier I am, generally.

You're right about the volume of data written; it's nearly as much as read, likely due to continuously syncing browsers - I leave my desktop on 24/7, and run 2 browsers, all of which probably doesn't help. It doesn't add up to an argument for high IOPS though.

I chose the Samsung drive primarily because of all the stories about premature SSD failures - all the drives I've bought have either been Intel or Samsung. I got this model because it was the 1TB option that was both SSD and either Samsung or Intel.

I cannot tell you how many days I've wasted replacing disks in home raid arrays, or before that recovering data from backups. I'm also done with trying to shuffle data between tiny SSDs and large spinning disks based on required speed of access. I keep all my bulky files on my ZFS NAS, but I don't worry about how many apps or games I have installed - 1T has, for now, been more than enough.

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#77
post #7

Earlier quoted context omitted.

It's not Government funded. There's a mandatory TV tax (for TV viewers), the fee of which is set by Government.

"Taxes" are money paid to the government for use in government funded activities.

https://en.wikipedia.org/wiki/Television_licensing_in_the_Un...

Re: Testing disks: Lessons from our odyssey selecting replacement SSDs

#78
post #59
post #56

Earlier quoted context omitted.

a consumer pc. the pro does not have the buffer the evo does. the evo is not a premium model, it is entry level cutting edge

That is not very specific, a consumer PC would be fine with a 750 Evo also, maybe two of them in raid 0 for twice the sequential read & write speed. I believe for most consumers, having more SSD storage per $ is more important.

a 750 evo is a sata drive, a 950 is an nvme drive. completely different technology. if my laptop has an nvme slot why would i buy a sata drive. 2 750s is not faster than 1 950
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