Shingled magnetic recording (SMR)
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@propagandalf Plotting to ten 8TB drives in parallel... that's some real next level stuff right there.
And heck yeah - we are proud members of the FX-8350 Burst miner club. AMD4LYFE.
To be clear, I kept the "Turn off Windows write-cache buffer flushing on the device" unchecked for my copies.
I also think you're right about the stagger size and/or giving the drives time to catch up, especially if you're writing to ten of them because that'll spread out the 'write load' more efficiently. I also noticed that these SMR drives reportedly have a feature where they can boost their writing speed temporarily. I actually saw this happen while copying to the 8TB external drives because during each mining round, the write speeds would drop back down to 30MB/s (due to the fact that the internal 8TB drives were being monopolized by the miner for the round I assume), but right after the round was over, they would boost up to almost 200MB/s for about 20 seconds before they settled back down to 130MB/s again. So just 20 seconds of semi-down time gave each drive a significant temporary boost.
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@sevencardz Thanks! AMD rox ;)
I did not know about this temporary boost. Is it a setting, or is it just a built-in feature that is always on?
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It's strange I guess I got lucky lol. 4 of my drives are the Seagate 8tb and they work perfectly fine. Never had an issue with them up to date :D and even sometimes a better read time than the non Seagate drives I have
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@propagandalf The storage review here talks about "burst write activity". Of particular interest are these lines:
"In our test we saw, as expected, the SMR drives took much longer for a traditional full backup, averaging 30MB/s. However we saw sustained read speeds during a 400GB VM recovery in excess of 180MB/s, which is really the core metric. Given the low cost/TB, the drives do very well here if the backup admin can get a little creative. Design your backup window to work with the lower sustained write performance (or design it to fit inside the burst write window completely) but still have your data ready at your fingertips without compromising restore speeds."
http://www.storagereview.com/seagate_archive_hdd_review_8tbI'm wondering if they had turned write caching ON during their full backup (assuming it was off) if the speeds would've gone from 30MB/s to 130MB/s like mine did. Or perhaps it only helps if you are writing massive 500GB files. That basically means these drives are almost as good as normal PMR drives if you can limit the workload to huge sequential writes - which I do by writing all the plots to NAS drives first and then copying them over.
Also, it seems that if you stagger your write operations so that you're not hammering the queue of write operations on the drive, then you take advantage of the burst speeds more effectively. Of course, this seems to work best if you have other drives you can write to while others are catching up based on propagandalf's results. They don't mention what burst speeds they got, but they do say "burst write speeds are in-line or surpassing traditional HDDs".
@Zeus If you plugged your drives in to the mobo via SATA or if you were lucky enough for your OS to automatically turn write caching on for the disk, then I'm not surprised you've never had an issue. I'm pretty sure the OS intentionally turned off write caching on the disk for me as a safety feature to avoid loss of data in situations where the user unplugs the external drive without properly disconnecting it in Windows. Of course, as long as you don't plan to unplug your drive in the middle of a write operation, then you don't need or want such a safety net.
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I had one of those 8TB Seagate Expansion drives and it failed after just a few days. I guess those drives are just terrible quality. I've had no problems with the 4TB / 5TB Seagate's.
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@ZapbuzZ Why not just use blagos version 1.0 cpu plotter its way faster now as long as you have a decentish cpu and it optimizes your plots straight away and works your way would take way too long. I have used fastcopy too it's a good program for copying things when you've got to copy lots of data uninterrupted and fast.
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@weaveR said in Shingled magnetic recording (SMR):
Why not just use blagos version 1.0 cpu plotter its way faster now as long as you have a decentish cpu and it optimizes your plots straight away and works your way would take way too long.
That program is really great, but where GPU plotter excels is when you can plot multiple HDDs simultaneously. For instance, I plotted 40TB in 24 hours (unoptimized, buffer mode) by connecting three GPUs to my mobo. I would not be able to plot that much in such a short time using CPU plotter unless I had multiple CPUs to work with. On average I had 41k nonces per minute on each GPU.
I'm not sure how long it will take for me to optimize these 40TB, but I think I am able to set each drive to optimize simultaneously as well. Could someone please post an example output for running plotoptimizer.exe on 2 or more plots if that is possible? Or do we have to run several instances of the program in order to achieve that?
@sevencardz Did you try to plot in direct mode with GPU plotter after turning on the write cache for the SMR drives? Or is that still a lost cause?
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@weaveR have used blagos cpu plotter but over 1 tb it slows down drastically I haven't the high end cpu nor gpu tech so I use the Cer Jenror plotter. No plot needs to be optimised until used for several months. However the plotter that I use requires the plot to be made contiguous (defragmented). I know I can make smaller plots with Blagos ploter v1.0 fastly but I prefer to make larger ones as to be afk. lol. @Propagandalf I don't use the GPU Plotter as it is slower than the CPU plotter that I use simply because I have a low profile Nvidia PCI-E v.20 graphics card. Besides, I prefer a system lag free plotting experience so i can surf the net whilst plotting (or mine for that matter)
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@RiskyFire @Burstde I think the higher failure rate may be due to the combination that these drives have no active cooling solution, huge 8TB capacity, and they use intensive read, modify, write operations due to the SMR architecture. I sent one back a few weeks ago after I wrote to it for a day because it was uncomfortably hot to the touch and the plastic had actually started to warp. Since then, I put these drives right on top of my computer's rear exhaust fan at the top of the case, which pushes air right into the bottom vents of the enclosures and I've had no issues with heat since.
@Propagandalf I haven't tried writing in direct mode to the 8TB Expansion drives with disk write caching on, but I fear that I would still see the terrible single digit MB/s speeds during the secondary 'fill in nonces' stage at some point just due to the SMR architecture. The plots have already copied over from my 8TB NAS drives, so I'm not in a position to test, but if I get some more of these SMR drives in the future, I'll certainly give it a shot.
I only used plotoptimizer once and I used the GUI, which is pretty simple, just point and shoot. However, it took so long because it has to rewrite the plots, and you need a place to write them to, so I just ended up just replotting the rest of what I had done up to that point in direct mode with GPU plotter.
What kind of read speeds are you getting now? Given that your plots are not optimized and have a small stagger size, I'd be concerned about slower read times.
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@Propagandalf Oh I do the same thing plotting multiple hard drives at once but instead of using multiple graphics cards I use multiple computers blagos cpu plotter doesn't lag the hell out of my main computer either which is nice unlike the GPU plotter but it does lag my mining PC but it still manages to mine while I'm doing that usually the plot scanning is just a bit slower.
Plotting 40TB is pretty impressive in 24 hours though it took me 35 hours to plot one hard drive that was 6TB and I didn't record how long it took on the mining PC I think it took a few more hours with blagos plotter but they were optimized plots. My computers aren't really bleeding edge technology though.
When I tried using the optimizer I think I remember it lagging my computers optimizing just one plot and the progress output was crazy but it's really annoying when the computers unusable I have to find something else to do lol. I do have a laptop though but it's got a bad keyboard that only works when it feels like to. I guess I could plug a keyboard in but I'd rather use a desktop.
@ZapbuzZ Never heard of that plotter before. Yeah I probably wouldn't make too many plot files if I was you I think I've heard that slows the plot scanning down when your mining but I do have quite a few plot files myself on some of the drives from when I was learning. Unfortunately I can't replot larger files easily being the nounces would overlap.
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@sevencardz said in Shingled magnetic recording (SMR):
What kind of read speeds are you getting now? Given that your plots are not optimized and have a small stagger size, I'd be concerned about slower read times.
I just watched task manager while the last block round was started, and clicked my way through the ten drives. It looked like I was averaging 23 MB/s on each one. Jminer says 238 MB/s average, which is probably the total amount that has been read in the program during a mining round, which seems consistent with 23 MB/s x10. My total plot size of 40 TB was read in 40.5 seconds, with 4x USB 3.0 controllers on duty. It is likely that my read speeds will increase dramatically when I get these plots optimized!
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I noticed the 8tb internal drives would be really hot too as I took them out to be replaced. Since then I took my drives out and set them into a BlacX Duet HDD Docking Station with a cheap usb fan pointed at them. Maybe that's why i haven't had to replace them any more.
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@Propagandalf It takes 20 seconds to scan my 50TB of optimized plots, so 40 seconds isn't bad at all.
@Burstde Yeah, I noticed that even compared to the 4TB Expansion drives sitting right next to the 8TB ones, that the 8TB ones were hotter to the touch just doing Burst mining until I put a fan right under their butts.
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@Propagandalf @sevencardz It takes me like 32 seconds to scan 28.3TB all the hard drives I'm using have slow RPM though.
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My WD external is about to get a circle cut out of its plastic for a vent fan. It it goes well I will post a photo but as far as internal drives go there are cooling solutions. Like a plate that screws on and fans vent the spindle bearings i saw on ebay. I bet water cooling cpu blocks could be attrached lol

