4 ms·

I checked the specs here: https://www.micron.com/content/dam/micron/global/public/products/storage/ssds/data-center/6600/6600-ion-nvme-ssd-product-brief.pdf htt

by throwaway2037 6mo ago

I checked the specs here: https://www.micron.com/content/dam/micron/global/public/products/storage/ssds/data-center/6600/6600-ion-nvme-ssd-product-brief.pdf https://www.micron.com/content/dam/micron/global/public/prod... The interface looks equiv to 4x PCIe 5.0. > Sequential read (MB/s): 13,700 > Sequential write (MB/s): 2,700 That is pretty awful write performance. Does anyone know more about this? I assume all of these hyperdense SSDs suffer from the same drawback. Also, I heard that the E3.L interface can support up to 16x lanes, but there are no practical commerical products at this point.

voxelghost 6mo ago
65 hours to restore a full backup
- xattt 6mo ago
  Yes, but with all that data, how much heavier does it get?
  - jurgemaister 6mo ago
    2.231705*10^-13 gram
    - hebelehubele 6mo ago
      :) A single speck of dust could throw off that measurement (~ 1.6 x 10^-7 grams)
  - didgetmaster 6mo ago
    It depends on the data. I heard that ones are heavier than zeros.
    - thrill 6mo ago
      Yes, this why drives come in the mail pre-wiped - it saves on shipping.
justsomehnguy 6mo ago
Extremely dense QLC chips. Still it's 2700-3000MByte, ie ~3GByte/second. What should worry way more is DWPD which is abysmal... on the first glance. But if you punch it in the calc it still would take ages to wear it out. SSD #1 SSD #2 SSD #3 Capacity (GB) 245000 245000 245000 Warranty (yr.) 3 3 3 DWPD 0.3 1 0.075 TBW (TB) 80482 268275 20121 TBW (PB) 80.483 268.275 20.121 PBW 80.483 268.275 20.121 GB/day 73500 245000 18375 Time period Average host-side write data rate (MB/s) needed for reaching DWPD value within specified time period 8 hr. 2552.08 8506.94 638.02 12 hr. 1701.39 5671.30 425.35 24 hr. 850.69 2835.65 212.67 https://wintelguy.com/dwpd-tbw-gbday-calc.pl https://wintelguy.com/dwpd-tbw-gbday-calc.pl
- _zoltan_ 6mo ago
  DWPD was the boogey man 10 years ago. everybody worried about it. now, nobody cares. I have over 500 NVMe drives in our deployment and the drive deaths are not due to wear.
  - markhahn 6mo ago
    then either your drives are overprovisioned or read-mostly. it's not that hard to hit 300 cycles on flash.
    - deleted 6mo ago
      [deleted]
    - _zoltan_ 6mo ago
      it's all 4TB or larger plus the drives do wear leveling internally.
  - throwaway2037 6mo ago
    > I have over 500 NVMe drives in our deployment and the drive deaths are not due to wear. This is high quality anecdata. What is the root cause of most of your drive deaths?
sheepscreek 6mo ago
A more convenient (and dare I say, faster) tape drive replacement for backups? They do make a good point, it would take 10*24TB drives working in the worst raid configuration to even come close to these speeds.
Aurornis 6mo ago
Consumer and data center drives play by different rules. The super high write speeds you see for consumer SSDs are usually achieved through tricks like using sections of the drive as a high-speed buffer and then using a background process to rewrite the data into the drive's high-density NAND storage during downtime. They can also use caching techniques that aren't resilient to power loss. They might allow burst performance that heats the drive up until it throttles. This is all fine and even desirable for a consumer who will only be writing for at most a minute or two, but with a 245TB server drive you need to assume the performance will be needed constantly. They target sustainable and predictable performance.

voxelghost 6mo ago

65 hours to restore a full backup

xattt 6mo ago
Yes, but with all that data, how much heavier does it get?
- jurgemaister 6mo ago
  2.231705*10^-13 gram
  - hebelehubele 6mo ago
    :) A single speck of dust could throw off that measurement (~ 1.6 x 10^-7 grams)
- didgetmaster 6mo ago
  It depends on the data. I heard that ones are heavier than zeros.
  - thrill 6mo ago
    Yes, this why drives come in the mail pre-wiped - it saves on shipping.

justsomehnguy 6mo ago

Extremely dense QLC chips. Still it's 2700-3000MByte, ie ~3GByte/second. What should worry way more is DWPD which is abysmal... on the first glance. But if you punch it in the calc it still would take ages to wear it out. SSD #1 SSD #2 SSD #3 Capacity (GB) 245000 245000 245000 Warranty (yr.) 3 3 3 DWPD 0.3 1 0.075 TBW (TB) 80482 268275 20121 TBW (PB) 80.483 268.275 20.121 PBW 80.483 268.275 20.121 GB/day 73500 245000 18375 Time period Average host-side write data rate (MB/s) needed for reaching DWPD value within specified time period 8 hr. 2552.08 8506.94 638.02 12 hr. 1701.39 5671.30 425.35 24 hr. 850.69 2835.65 212.67 https://wintelguy.com/dwpd-tbw-gbday-calc.pl https://wintelguy.com/dwpd-tbw-gbday-calc.pl

_zoltan_ 6mo ago
DWPD was the boogey man 10 years ago. everybody worried about it. now, nobody cares. I have over 500 NVMe drives in our deployment and the drive deaths are not due to wear.
- markhahn 6mo ago
  then either your drives are overprovisioned or read-mostly. it's not that hard to hit 300 cycles on flash.
  - deleted 6mo ago
    [deleted]
  - _zoltan_ 6mo ago
    it's all 4TB or larger plus the drives do wear leveling internally.
- throwaway2037 6mo ago
  > I have over 500 NVMe drives in our deployment and the drive deaths are not due to wear. This is high quality anecdata. What is the root cause of most of your drive deaths?

sheepscreek 6mo ago

A more convenient (and dare I say, faster) tape drive replacement for backups? They do make a good point, it would take 10*24TB drives working in the worst raid configuration to even come close to these speeds.

Aurornis 6mo ago

Consumer and data center drives play by different rules. The super high write speeds you see for consumer SSDs are usually achieved through tricks like using sections of the drive as a high-speed buffer and then using a background process to rewrite the data into the drive's high-density NAND storage during downtime. They can also use caching techniques that aren't resilient to power loss. They might allow burst performance that heats the drive up until it throttles. This is all fine and even desirable for a consumer who will only be writing for at most a minute or two, but with a 245TB server drive you need to assume the performance will be needed constantly. They target sustainable and predictable performance.