this post was submitted on 25 Sep 2023
25 points (93.1% liked)

Selfhosted

39964 readers
339 users here now

A place to share alternatives to popular online services that can be self-hosted without giving up privacy or locking you into a service you don't control.

Rules:

  1. Be civil: we're here to support and learn from one another. Insults won't be tolerated. Flame wars are frowned upon.

  2. No spam posting.

  3. Posts have to be centered around self-hosting. There are other communities for discussing hardware or home computing. If it's not obvious why your post topic revolves around selfhosting, please include details to make it clear.

  4. Don't duplicate the full text of your blog or github here. Just post the link for folks to click.

  5. Submission headline should match the article title (don’t cherry-pick information from the title to fit your agenda).

  6. No trolling.

Resources:

Any issues on the community? Report it using the report flag.

Questions? DM the mods!

founded 1 year ago
MODERATORS
ruud@lemmy.world
Loki@lemmy.world
CannaVet@lemmy.world
HybridSarcasm@lemmy.world
devve@lemmy.world
HybridSarcasm@lemmy.hybridsarcasm.xyz
25
Help with understanding throughput of pcie and hard drives (lemmy.world)
submitted 1 year ago* (last edited 1 year ago) by a_fancy_kiwi@lemmy.world to c/selfhosted@lemmy.world
10 comments fedilink hide all child comments
 

I've been interested in building a DIY NAS out of an SBC for a while now. Not as my main NAS but as a backup I can store offsite at a friend or relative's house. I know any old x86 box will probably do better, this project is just for the fun of it.

The Orange Pi 5 looks pretty decent with its RK3588 chip and M.2 PCIe 3.0 x4 connector. I've seen some adapters that can turn that M.2 slot into a few SATA ports or even a full x16 slot which might let me use an HBA.

Anyway, my question is, assuming the CPU isn't a bottle neck, how do I figure out what kind of throughput this setup could theoretically give me?

After a few google searches:

  • PCIe Gen 3 x4 should give me 4 GB/s throughput
  • that M.2 to SATA adapter claims 6 ~~GB/s~~ Gb/s throughput
  • a single 7200rpm hard drive should give about 80-160MB/s throughput

My guess is that ultimately, I'm limited by that 4GB/s throughput on the PCIe Gen 3 x4 slot but since I'm using hard drives, I'd never get close to saturating that bandwidth. Even if I was using 4 hard drives in a RAID 0 config (which I wouldn't do), I still wouldn't come close. Am I understanding that correctly; is it really that simple?

you are viewing a single comment's thread
view the rest of the comments
[–] cmnybo@discuss.tchncs.de 10 points 1 year ago (1 children)

No matter what adapter you use, you will be limited to the throughput of the PCIe 3 x4 port.

SATA is 6 gigabits per second, not gigabytes. The SATA adapter is only PCIe 3 x2 which would limit the throughput if you used it with SSDs, but it will still have plenty of bandwidth for hard drives.

[–] a_fancy_kiwi@lemmy.world 4 points 1 year ago

SATA is 6 gigabits per second, not gigabytes.

Oh shit. I misread the Amazon description. Thanks for catching that and thanks for your response