5 ms·

I'm pretty sure they mean HDDs as they write hard disks in each paragraph below.

by timenova 3y ago

SushiHippie 3y ago
I don't think there are HDDs that can read 300MB/s
- dale_glass 3y ago
  https://www.seagate.com/content/dam/seagate/migrated-assets/www-content/datasheets/pdfs/exos-2x14-DS2015-3-2007US-en_US.pdf https://www.seagate.com/content/dam/seagate/migrated-assets/... Claims 500 MB/s. But of course your chances of getting that from a hard disk are far less than from a SSD.
- bravetraveler 3y ago
  I mostly play with 7200RPM consumer drives, they hang around there in ideal situations: sequential non-fragmented reads Not to put stock in the assertion, I have no idea what the article intends
- breck-fresen 3y ago
  Spinning HDDs have ~3MB on the outer track and 1MB on the inner track. 7200rpm/60 * 3MB = 360MB/second for sequential outer track reads. Source: I wrote S3's on-disk placement algorithm
  - araes 3y ago
    Do you happen to be the writer of this technical article on AWS? [1] If not, someone on Seth Markle's team over at Amazon wrote a pretty fascinating article on the S3 architecture. Never actually heard the "airplane at 75 MPH over a grass lawn comparison" before. This [2] aggregate workload graph/video is pretty sweet too. Very matrixy while still actually being fairly clear about what's going on. Imagery implies S3 (at writing) had a 3.7 PB bucket size with 2.3M req/sec. Worked out to 143 hard drives (storage constrained result) and 19,000 hard drives for the I/O constrained result. Kind of an interesting counterpoint to the article. Here's what really large workload / access rate systems with spikey, intermittent workloads are structured like. [1] https://www.allthingsdistributed.com/2023/07/building-and-operating-a-pretty-big-storage-system.html https://www.allthingsdistributed.com/2023/07/building-and-op... [2] https://www.allthingsdistributed.com/videos/fast-agg-graph-compressed-small.mp4 https://www.allthingsdistributed.com/videos/fast-agg-graph-c...
- tecleandor 3y ago
  Current high capacity enterprise HDDs (Like an Exos 24 or an WD Gold 24), in ideal conditions, reach around 250-280MiB/s, so quite sort of 300 as a regular number. Probably they are pulling info from an older article or just using a round number to make it more clear. Edit note: As a sibling comment says, Seagate had for a while a "2x" Exos model that had dual actuators and claimed ~500Mbytes/s of max transfer speed. But seem discontinued or unavailable and didn't have much success (out of the datacenter at least)
- magicalhippo 3y ago
  My 20TB WDs get pretty close, around 270MB/s sequential read[1]. Higher density means higher sequential speed, so if not the 22TB models then the 24TB should reach that. [1]: https://www.kitguru.net/components/hard-drives/simon-crisp/wd-ultrastar-dc-hc560-20tb-hdd-review/all/1/ https://www.kitguru.net/components/hard-drives/simon-crisp/w...
- deleted 3y ago
  [deleted]

I'm pretty sure they mean HDDs as they write hard disks in each paragraph below.

SushiHippie 3y ago

I don't think there are HDDs that can read 300MB/s

dale_glass 3y ago
https://www.seagate.com/content/dam/seagate/migrated-assets/www-content/datasheets/pdfs/exos-2x14-DS2015-3-2007US-en_US.pdf https://www.seagate.com/content/dam/seagate/migrated-assets/... Claims 500 MB/s. But of course your chances of getting that from a hard disk are far less than from a SSD.
bravetraveler 3y ago
I mostly play with 7200RPM consumer drives, they hang around there in ideal situations: sequential non-fragmented reads Not to put stock in the assertion, I have no idea what the article intends
breck-fresen 3y ago
Spinning HDDs have ~3MB on the outer track and 1MB on the inner track. 7200rpm/60 * 3MB = 360MB/second for sequential outer track reads. Source: I wrote S3's on-disk placement algorithm
- araes 3y ago
  Do you happen to be the writer of this technical article on AWS? [1] If not, someone on Seth Markle's team over at Amazon wrote a pretty fascinating article on the S3 architecture. Never actually heard the "airplane at 75 MPH over a grass lawn comparison" before. This [2] aggregate workload graph/video is pretty sweet too. Very matrixy while still actually being fairly clear about what's going on. Imagery implies S3 (at writing) had a 3.7 PB bucket size with 2.3M req/sec. Worked out to 143 hard drives (storage constrained result) and 19,000 hard drives for the I/O constrained result. Kind of an interesting counterpoint to the article. Here's what really large workload / access rate systems with spikey, intermittent workloads are structured like. [1] https://www.allthingsdistributed.com/2023/07/building-and-operating-a-pretty-big-storage-system.html https://www.allthingsdistributed.com/2023/07/building-and-op... [2] https://www.allthingsdistributed.com/videos/fast-agg-graph-compressed-small.mp4 https://www.allthingsdistributed.com/videos/fast-agg-graph-c...
tecleandor 3y ago
Current high capacity enterprise HDDs (Like an Exos 24 or an WD Gold 24), in ideal conditions, reach around 250-280MiB/s, so quite sort of 300 as a regular number. Probably they are pulling info from an older article or just using a round number to make it more clear. Edit note: As a sibling comment says, Seagate had for a while a "2x" Exos model that had dual actuators and claimed ~500Mbytes/s of max transfer speed. But seem discontinued or unavailable and didn't have much success (out of the datacenter at least)
magicalhippo 3y ago
My 20TB WDs get pretty close, around 270MB/s sequential read[1]. Higher density means higher sequential speed, so if not the 22TB models then the 24TB should reach that. [1]: https://www.kitguru.net/components/hard-drives/simon-crisp/wd-ultrastar-dc-hc560-20tb-hdd-review/all/1/ https://www.kitguru.net/components/hard-drives/simon-crisp/w...
deleted 3y ago
[deleted]