←back to thread

420 points speckx | 1 comments | | HN request time: 0.001s | source
Show context
dylan604 ◴[] No.44533476[source]
SSD speeds are nothing short of miraculous in my mind. I come from the old days of striping 16 HDDs together (at a minimum number) to get 1GB/s throughput. Depending on the chassis, that was 2 8-drive enclosures in the "desktop" version or the large 4RU enclosures with redundant PSUs and fans loud enough to overpower arena rock concerts. Now, we can get 5+GB/s throughput from a tiny stick that can be used externally via a single cable for data&power that is absolutely silent. I edit 4K+ video as well, and now can edit directly from the same device the camera recorded to during production. I'm skipping over the parts of still making backups, but there's no more multi-hour copy from source media to edit media during a DIT step. I've spent many a shoot as a DIT wishing the 1s&0s would travel across devices much faster while everyone else on the production has already left, so this is much appreciated by me. Oh, and those 16 device units only came close to 4TB around the time of me finally dropping spinning rust.

The first enclosure I ever dealt with was a 7-bay RAID-0 that could just barely handle AVR75 encoding from Avid. Just barely to the point that only video was saved to the array. The audio throughput would put it over the top, so audio was saved to a separate external drive.

Using SSD feels like a well deserved power up from those days.

replies(8): >>44533735 #>>44534375 #>>44535266 #>>44535471 #>>44536311 #>>44536501 #>>44539458 #>>44539872 #
jorvi ◴[] No.44535471[source]
It's not really the SSDs themselves that are incredibly fast (they still are somewhat), it's mostly the RAM cache and clever tricks to make TLC feel like SLC.

Most (cheap) SSDs their performance goes off a cliff once you hit the boundary of these tricks.

replies(2): >>44535868 #>>44536447 #
forrestthewoods ◴[] No.44536447[source]
> once you hit the boundary of these trick

Tell me more. When do I hit the boundary? What is perf before/after said boundary? What are the tricks?

Tell me something actionable. Educate me.

replies(2): >>44537514 #>>44539518 #
jdiff ◴[] No.44537514[source]
Your tone is quite odd here. I'm having difficulty parsing your intention, but I'm going to assume you're being genuine because why not.

For the RAM cache, you hit the boundaries when you exhaust the RAM cache. It performs faster, but is smaller and once full, data has to be off/loaded at the rate of the slower backing NAND. It might not be RAM, either, sometimes faster SLC NAND is used for the cache.

It's not really possible to describe it much more concretely than that beyond what you've already been told, performance falls off a cliff when that happens. How long "it" takes, what the level of performance is before and after, it all depends on the device.

There are many more tricks that SSD manufacturers use, but caching is the only one I know of related to speed so I'll leave the rest in the capable hands of Google.

replies(3): >>44537878 #>>44538489 #>>44538662 #
forrestthewoods ◴[] No.44538662[source]
My tone is a combination of genuine curiosity and moderate annoyance at a dismissive but unhelpful comment.

RootsComment: SSD speed is miraculous! Jorvis: well ackshually is just RAM and tricks that run out Me: your comment provides zero value

I am annoyed by well ackshually comments. I’d love to learn more about SDD performance. How is the ram filled? How bad is perf when you cache miss? What’s worse case perf? What usage patterns are good or bad? So many interesting questions.

replies(2): >>44538915 #>>44541163 #
dylan604 ◴[] No.44538915{3}[source]
Right? I’m comparing my direct experience of enduring the pain of slower than Christmas HDDs to the incredible speeds of SSDs, and get a well actually it’s not SSDs that are fast blah blah. Look dude, I don’t care about your magic smoke that you’re so smart you know how the smoke is made. I just care that I can transfer data at blisteringly fast speeds. I couldn’t care less about QLC, SLC, or TLC because reading/writing at >2GB/s is all the tender loving care I need. Don’t rain on my parade because you’re jaded.
replies(1): >>44538946 #
1. forrestthewoods ◴[] No.44538946{4}[source]
I haven’t had a spinning platter in my dev machine since I think 2008 or 2009. Even back then an SSD was the single biggest upgrade I’d seen the first 3D accelerator cards in the late 90s. (Oh god I’m old).

More recently we saw SSDs get added to video game consoles and load times are about 4x faster. And that’s with code/data optimized for a spinning plate not an SSD.

I know they aren’t actually magic. But they might as well be! I’d love to hear details on what weird conditions reduce their performance by 10x. That’d be cool and fun to know. Alas.