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Just want a confirmation: SSDs start slowing down once you've written a shitload to them, right? Backstory: Have an app that writes to a circular buffer at ~5MB/s 24x7 to a WD 1TB Blue 3d (and has for like a year and a bit) - only now starting to see (minor) spikes in latency on occasion that haven't really seen before when the write queue goes big. Smart results are perfectly fine - and it looks like the WD ncache buffer tech which uses SLC is almost perfect for this app. (Smart reports 5TB written to TLC, and 62TB to SLC, host writes of 56TB) unknown fucked around with this message at 20:48 on Jan 29, 2019 |
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Jan 29, 2019 20:44
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| # ¿ Apr 25, 2024 19:03 |
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Thanks, that makes sense - drive is like 80% empty, and there's no bad block/realloc errors at all in smart. But with the huge cache hit ratio I was wondering if the SLC/ncache portion of ~15GB (described here: https://www.techarp.com/reviews/1tb-sandisk-ultra-3d-ssd-review/2/) was getting smashed apart. But further research puts SLC at 90-100k writes before an issue. (So like 125-150TB) It's probably something else throwing poo poo into the write queue causing the delay - I am talking about a 1ms "spike" here.
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Jan 29, 2019 22:17
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Klyith posted:AFAIK the SLC isn't a static area of the NAND, it gets moved around to work with the overall wear leveling. Newer drives don't even have a fixed size allocated to SLC mode. Writes in SLC mode are much less damaging to the cell, much like getting hit with a bat is nicer than getting shot with a bullet. The bat and bullet might have the same amount of kinetic energy, but the bullet is more concentrated. Thanks for the data, quite interesting to read. I wouldn't be surprised that there's some garbage collection type issues happening - the WD Blue 3D is literally a consumer level drive that was thrown in as a test, and this workload is really perfect enterprise type (solid writes - literally the os disk cache covers the reads I think) - probably should just spring for a samsung pro. Now that I think of it, I'm wondering if I can just mount a ramdisk for this app.
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Jan 30, 2019 23:41
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Klyith posted:AFAIK the SLC isn't a static area of the NAND, it gets moved around to work with the overall wear leveling. Newer drives don't even have a fixed size allocated to SLC mode. Writes in SLC mode are much less damaging to the cell, much like getting hit with a bat is nicer than getting shot with a bullet. The bat and bullet might have the same amount of kinetic energy, but the bullet is more concentrated. Just an update - looks like it wasn't the ssd at all, but an update was rolled into the app (written in java no less) that was screwing up more and more (probably some failed garbage collection) giving a false drive alert. So, for people keeping track - a consumer level SSD (WD Blue 3d - 1TB) with a 24/7 writing stream to it for over a year is perfectly happy with the abuse. Smart reports are still saying 100% life left in it with zero errors on the drive.
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Feb 5, 2019 18:55
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https://www.theregister.co.uk/2019/11/25/hpe_ssd_32768/ https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-a00092491en_us quote:
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Nov 26, 2019 16:12
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Mental Hospitality posted:I probably should have asked here before spending money... I have a whole bunch of them at work that are being used as cache drives for applications that are basically a 25/75 read/write ratio (yes) running 24x7. So basically the worst thing you can do to them. Not one bad one yet over the past year and smart reports are still giving me the 2 thumbs up.
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Jun 6, 2020 19:10
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Thought this might be interesting benchmark for people on a new system upgrade (Ryzen 3600+B550 motherboard) for me - 3 generations of drives: NVMe/WD SN850 (@pcix4 - max:7000/4100MBps), SSD/WD Blue (@sata6 - max: 560/530MBps), and HDD/Seagate Ironwolf (max:180MBps) .
unknown fucked around with this message at 20:28 on Mar 22, 2021 |
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Mar 22, 2021 20:19
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I enabled bit locker on my sn850 recently and it was fun to watch it encrypt at 1 GByte/s (vs 125MByte/s for a sata ssd), but that's about it for performance improvements on day to day. There's maybe a couple of seconds shaved off here and there for loading stuff (email client and some games), but that's about it.
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Jul 2, 2021 14:28
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| # ¿ Apr 25, 2024 19:03 |
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Just for people's curiosity about longevity - here's the smart output from a WD Blue 3D 1TB drive that's getting brutalized as a caching disk with a constant write of around 1-2MB/s to it for the past 33,000 hours (ie: almost 4 years - when they came out). Yeah, don't worry about them wearing out.
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Sep 22, 2021 15:03
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