Slow communication through lan

Hi, I have a Pi Zero with an ext HDD and a powered hub. The read/write speed through wifi (from laptop running ubuntu) is about 600kb/s and the iperf sais that the transfer speed is around 3.5 mb/s. Do you have any idea what causes this slow transfer speed?

The transfer speed between ext HDD and int SD card is 10 mB/s and also it is around 10mB/s between two ext drivers.

Thanks in advance.

Check your wifi signal and connection speed with wavemon

I had a similar problem with my RPi1, what type of WiFi dongle are you using?

Check dmesg for messages about RF_Save. If you are using a Realtek 8188/8192 dongle and are seeing those messages then the next OSMC update (scheduled for Sunday UK time) should very much improve the issue for you.

@fzinken this is the output of the wavemon.

@yknivag it is a simple 802.11 dongle, but I used another one before it and I experienced the same problem. This is the output of dmesg (only the part that corresponds to the wifi):

[ 3.876603] usb 1-1.2.3: New USB device found, idVendor=148f, idProduct=5370
[ 3.876637] usb 1-1.2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 3.876656] usb 1-1.2.3: Product: 802.11 n WLAN
[ 3.876671] usb 1-1.2.3: Manufacturer: Ralink
[ 3.876686] usb 1-1.2.3: SerialNumber: 1.0

[ 12.190206] ieee80211 phy0: rt2x00_set_rt: Info - RT chipset 5390, rev 0502 detected
[ 13.098667] ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 5370 detected
[ 13.456672] ieee80211 phy0: Selected rate control algorithm ‘minstrel_ht’
[ 13.483861] usbcore: registered new interface driver rt2800usb
[ 14.280178] systemd-journald[144]: Received request to flush runtime journal from PID 1
[ 15.910458] ieee80211 phy0: rt2x00lib_request_firmware: Info - Loading firmware file ‘rt2870.bin’
[ 15.915898] ieee80211 phy0: rt2x00lib_request_firmware: Info - Firmware detected - version: 0.29[ 16.578890] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 18.109893] wlan0: authenticate with 68:17:29:c0:30:af
[ 18.179444] wlan0: send auth to 68:17:29:c0:30:af (try 1/3)
[ 18.183764] wlan0: authenticated
[ 18.208460] wlan0: associate with 68:17:29:c0:30:af (try 1/3)
[ 18.212522] wlan0: RX AssocResp from 68:17:29:c0:30:af (capab=0x411 status=0 aid=1)
[ 18.226553] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 18.235428] wlan0: associated

You’re using a Ralink 5370 so won’t be affected by the Realtek 8192 issue fixed in yesterday’s update.

I’ll let @fzinken comment in more detail on the wavemon output as I’m not familiar with that program.

Well you should get a bit more than the 3.5 mb/s that iperf gives you.
How does iperf with -R looks like?

With a 72Mbit wireless connection depending on your congestions you should at least get something close to 20mb/s

@fzinken Running iperf -s on my pc and running iperf -c <address> -r on osmc I got: 3.5Mbit/s and 5.1Mbit/s

I assume you used a capital “R” which is for reverse? Because that is what I wanted to compare up versus down.

Anyhow values really look not healthy for the signal quality you have. I get similar values but I have link quality at 67% and signal level at -65dBm.

So other than the normal wireless suggestions (e.g. change channel and ensure that country is set correctly) not much I can advice here, sorry.

Just looked at the wavemon output again, 8895 mac retries with only so little data transferred is really odd. But once more no idea what is causing it in your specific case.
I assume power supply is up to the task?

yes, the power supply can provide 2.4A

The rated output current is not all that needs to be taken into account. The Raspberry Pi requires a “constant voltage” supply, not a “constant current” supply. “Adapters” designed as chargers are primarily designed to supply a constant current for most of the time, whereas the Pi requires a guaranteed 5v irrespective of the current drawn.