High smb upload-download speed discrepancies.

Marcin · February 11, 2021 at 3:54 PM

Dear All.

I hope someone can explain something to me, and hopefully help me find a solution.

I have an Odroid C2 with LibreElec connected to home router via gigabit ethernet cable. One HDD drive for media strorage is connected to Odroid via USB port. Hdd is accesible by smb from home laptop.
My Laptop connects with home network over 5GHz wifi. Laptop with windows 10, wifi adapter is an Intel AC-8265.

The problem is that I can download data from that shared hdd relatively fast (about 280Mbps) but uploading the data to the hdd is a lot slower (20 - 50

Mbps).

Please see attached screenshot from iperf3 when odroid is a client with comparison when it's a server. This test also shows huge dicrepancies between upload and download.

Since I more frequently upload data to the odroid's hdd (photos, recordings etc) I would benefit from higher trasfer rates to the hdd, than from it.

Can someone explain this please and possibly advise?

Things that make no difference:

Changing wifi channels,

Changing laptop wifi adapter drivers,

Changing usb port where hdd is connected

Any help appreciated.

Kind regards

Marcin

Jogee · February 12, 2021 at 3:43 AM

Hard drives are slower at writing than reading, in general. But I've not personally noticed such a big offset. It could be a drive or enclosure limitation, but you've not specified any make/model info. 280 Mbps is a good USB2 read speed, especially when pulled over a wifi connection.

It may not be the fault of the wifi. Have you considered it could be the USB interface (the drive enclosure) or the Odroid itself? Have you done any testing on that side?

How is the USB HDD being powered, from the Odroid usb ports or external AC adapter. If not external AC, maybe the Odroid can't keep up the power.

Consider testing:

with your laptop connected via ethernet to your home router (hopefully it has an ethernet connection) to eliminate typical wireless issues.
read/write speeds of your USB HDD on your laptop, as a means to compare relative speeds and eliminate possibilities.
uploading from your laptop to some other network device's internal storage (not usb attached) if possible to see if the speed discrepancy follows (would help to eliminate the Odroid itself).
with a USB thumb drive instead of the USB HDD.

Good luck.

Marcin · February 12, 2021 at 8:19 AM

Hi Jogee

Thank you for your reply.

Connecting a laptop with ethernet cable to the router was a great idea. Now when I copy files between my laptop and the shared HDD I am getting about the same read and write speeds of 25 - 40 MBytes/s (200 - 300 Mbps), which is really good. It's a relatively old 3,5" 2tb seagate with it's own power adapter.

We do know this now.

- It is not an HDD issue.

- It is not an Odroid issue.

One thing remaining is my wireless router, which I think may be the problem, as it is one provided from my ISP.

The other thing is the wireless adapter in my laptop.

Kind regards

Marcin

Marcin · October 16, 2021 at 7:34 PM

My ISP updated the firmware in their modem-router. Also my neighbours wifi, which had a very strong signal is recently missing. Now my transfers are as below screenshots.

I am quite happy with the speeds. Alhough still not sure if it was the modem firmware or interference from other wifi networks, I think we can close this thread.

Kind regards

Marcin