191–200 of 353 posts
Earlier quoted context omitted.
Sounds kinda like the people who thought that bundling a bunch of bad mortgage debt together in slices could get it rated AAA.
Reminds me of a saying from the first dot.com crash. (Or at least I heard it then first.) Tying two bricks together doesn't make them float.
There is one big problem that I've not seen anyone else point out with systems like this. I know because I did the calculation early on with Peergos and came to the conclusion that it doesn't work. The problem comes when you want to store multiple files. If the corresponding erasure code fragments from different files are not stored on the same server then you don't have correlated failures. Contrast this with a typi…
ordinary raid has very slow recovery because it’s concentrated on a hot spot of a new drive. plus recovery waits for a new drive to be inserted (double stupid).
when fragment placement is randomized, recovery is widely distributed and can happen in less total time so lower chance of data loss.
Yep. Stopped reading right there. HDDs use ~15 watts when they boot up. I experienced this and I never allocate less than 20 watts / hard disk.
There is one big problem that I've not seen anyone else point out with systems like this. I know because I did the calculation early on with Peergos and came to the conclusion that it doesn't work. The problem comes when you want to store multiple files. If the corresponding erasure code fragments from different files are not stored on the same server then you don't have correlated failures. Contrast this with a typi…
totally false ordinary raid has very slow recovery because it’s concentrated on a hot spot of a new drive. plus recovery waits for a new drive to be inserted (double stupid). when fragment placement is randomized, recovery is widely distributed and can happen in less total time so lower chance of data loss.
Earlier quoted context omitted.
totally false ordinary raid has very slow recovery because it’s concentrated on a hot spot of a new drive. plus recovery waits for a new drive to be inserted (double stupid). when fragment placement is randomized, recovery is widely distributed and can happen in less total time so lower chance of data loss.
I didn't say anything about speed of recovery because it's not relevant. Recovery can't happen at all if enough fragments aren't online. The maths says that with unncorelated fragment placement, and thus uncorrelated failures, and with enough data, you are basically guaranteed to lose data. Try doing the maths for an entire filesystem, where each file/block is individually erasure coded.
Speed of recovery is crucial, because that’s your window of vulnerability to multiple failures. For example. try raid 5 on giant drives. The chances of losing a second drive during recovery is very likely.
Earlier quoted context omitted.
Where do I find the introduction what Sia is? I tried clicking around in the headers from OP, but couldn't find it within my very lazy tolerance.
Website: https://sia.tech/ Also take a look at Skynet, a file sharing protocol built on top of Sia: https://siasky.net/
I worked on the design of Dropbox's exabyte-scale storage system, and from that experience I can say that these numbers are all extremely optimistic, even with their "you can do it cheaper if you only target 95% uptime" caveat. Networking is much more expensive, labor is much more expensive, space is much more expensive, depreciation is faster than they say, etc etc. I don't think the authors have ever done any actua…
> Hard drives are a surprisingly low percentage of the cost of a storage system THIS! There's no use of a 2TB storage if you can't upload/download this amount each month
Earlier quoted context omitted.
> Using "8x 4 way SATA data splitters". There's no such thing as a passive SATA data splitter.
it's probably a SAS/Sata controller, and the sas interface split to 4x sata.
There is way too much hand-waving and assuming going on this article. It is a load of BS that does not take into account real-world inefficiencies. e.g. sometimes buying in bulk is more expensive than buying at retail, esp when you need consistent supply. Sure, you may need only an hour of sysadmin time a day, but what sysadmin will let you employ them an hour a day? The buildout did not list a CPU. The assumptions a…
It did, or does now anyway, the RYZEN 3 1200 for $95.
EDIT: Although the better option is the 3200G so that you can actually get a display output from the thing. Same price, so it doesn't really change anything, but it does cut the CPU core count down a bit if that matters at all.
That said the buildout still doesn't work because you can't actually plug the "sata splitter" cable they linked into the motherboard. Because the splitter was actually a 4-lane SAS SFF-8087 breakout cable, and there's no consumer motherboard with 8x of those connectors on it. Good luck finding even 1 or 2 of those connectors on a consumer board, and it sure as hell won't be at dirt cheap prices.
So you either need 4x the computers they calculated, or you need to budget for add-in SATA/SAS controller cards. Which, because they aren't used in consumer land, are not cheap. You could go used, but that's still going to increase the bottom line (and won't be a reliable source of parts)
They also aren't factoring in assembly time nor budgeting for that. Building these isn't going to go very quickly.