Troubleshooting LAN issue

General Discussion
1

Hi.

I’m experiencing what appears to be some sort of issue with my LAN between my Kodi install (OSMC running on a Vero 4K+) that’s connected via Ethernet to my RPi (3B), which is where my media drive is connected via USB. I’m starting here, because the only thing in my setup that has (beknownst to me) changed prior to this issue arising is a recent DietPi update to 18.5.x; not sure why this would be the culprit, but I have to start somewhere…

The new issue is that, when playing a video off the media drive, Kodi isn’t able to fill the video cache to match playback, so playback eventually fails. Here’s what the Dietpi-Benchmark results look like for my media drive:

Filesystem benchmark results:                                                                                        │ 
                                          │                                                                                                                      │ 
                                          │  - File path = /mnt/media/dietpi-benchmark_testfile                                                                  │ 
                                          │  - Test size = 100 MiB                                                                                               │ 
                                          │  - WRITE     = 22 MiB/s                                                                                              │ 
                                          │  - READ      = 26 MiB/s

And here’s what ethtool has to say about the interface from which the RPi is connected to my LAN (via a USB3 → Ethernet dongle):

Settings for eth1:
	Supported ports: [ TP	 MII ]
	Supported link modes:   10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Half 1000baseT/Full
	Supported pause frame use: No
	Supports auto-negotiation: Yes
	Supported FEC modes: Not reported
	Advertised link modes:  10baseT/Half 10baseT/Full
	                        100baseT/Half 100baseT/Full
	                        1000baseT/Full
	Advertised pause frame use: No
	Advertised auto-negotiation: Yes
	Advertised FEC modes: Not reported
	Link partner advertised link modes:  10baseT/Half 10baseT/Full
	                                     100baseT/Half 100baseT/Full
	                                     1000baseT/Half 1000baseT/Full
	Link partner advertised pause frame use: Symmetric Receive-only
	Link partner advertised auto-negotiation: Yes
	Link partner advertised FEC modes: Not reported
	Speed: 1000Mb/s
	Duplex: Full
	Auto-negotiation: on
	Port: MII
	PHYAD: 3
	Transceiver: internal
	Supports Wake-on: pg
	Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
	Link detected: yes

If nothing here jumps out at anyone or there aren’t other worthwhile diagnostics I can run on the DietPi side, I’ll move on to looking at the drive. Can’t believe it would be failing already, but who knows…

Thanks!

2

On Raspberry Pi, there was a kernel update released by RPI Foundation in parallel. Maybe this has some impacht. If you have a backup, you could restore to check. Onother option is to switch back to oldstable kernel.

1 Like
3

Thank you for the reply. I’m going to try installing iperf3 on my OSMC box and see if I can notice any issues between that and the RPi, too, just to cross that off the list.

What does the command look like for reverting to oldstable? Some version of dietpi-update?

4

The kernel has no relation to DietPi. It’s developed by Raspberry Fondation independently from DietPi. This is the stock kernel for all RPI SBC. To downgrade your current kernel version, you can use rpi-update GitHub - raspberrypi/rpi-update: An easier way to update the firmware of your Raspberry Pi 

apt install rpi-update
sudo rpi-update oldstable
reboot

This should downgrade your kernel from 6.1.19 to 5.10.103

1 Like
5

Do the R/W speeds from Dietpi-Benchmark seem inline with what you’d expect from the RPI 3 B’s USB 2 port? If it’s capable of 480Mb/s, wouldn’t that be ~457MiB/s in the benchmark? Seems like a big gap between 26MiB/s and 457MiB/s.

6

FWIW, some Iperf output. Seems like it’s pretty much at max for USB2.

RPi → OSMC:

iperf3 -R -c 192.168.50.103            
Connecting to host 192.168.50.103, port 5201
Reverse mode, remote host 192.168.50.103 is sending
[  5] local 192.168.50.119 port 50534 connected to 192.168.50.103 port 5201
[ ID] Interval           Transfer     Bitrate
[  5]   0.00-1.00   sec  33.5 MBytes   281 Mbits/sec                  
[  5]   1.00-2.00   sec  33.2 MBytes   278 Mbits/sec                  
[  5]   2.00-3.00   sec  33.3 MBytes   280 Mbits/sec                  
[  5]   3.00-4.00   sec  33.3 MBytes   279 Mbits/sec                  
[  5]   4.00-5.00   sec  33.3 MBytes   280 Mbits/sec                  
[  5]   5.00-6.00   sec  33.3 MBytes   279 Mbits/sec                  
[  5]   6.00-7.00   sec  33.3 MBytes   280 Mbits/sec                  
[  5]   7.00-8.00   sec  33.3 MBytes   279 Mbits/sec                  
[  5]   8.00-9.00   sec  33.6 MBytes   282 Mbits/sec                  
[  5]   9.00-10.00  sec  33.3 MBytes   279 Mbits/sec                  
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.04  sec   334 MBytes   279 Mbits/sec    0             sender
[  5]   0.00-10.00  sec   333 MBytes   280 Mbits/sec                  receiver

…and back:

iperf3 -c 192.168.50.103            
Connecting to host 192.168.50.103, port 5201
[  5] local 192.168.50.119 port 50544 connected to 192.168.50.103 port 5201
[ ID] Interval           Transfer     Bitrate         Retr  Cwnd
[  5]   0.00-1.00   sec  27.5 MBytes   230 Mbits/sec  583   42.4 KBytes       
[  5]   1.00-2.00   sec  22.2 MBytes   187 Mbits/sec  361   45.2 KBytes       
[  5]   2.00-3.00   sec  28.9 MBytes   242 Mbits/sec  439   56.6 KBytes       
[  5]   3.00-4.00   sec  29.3 MBytes   246 Mbits/sec  467   60.8 KBytes       
[  5]   4.00-5.00   sec  29.5 MBytes   248 Mbits/sec  550   52.3 KBytes       
[  5]   5.00-6.00   sec  27.3 MBytes   229 Mbits/sec  455   49.5 KBytes       
[  5]   6.00-7.00   sec  22.2 MBytes   186 Mbits/sec  251   62.2 KBytes       
[  5]   7.00-8.00   sec  29.3 MBytes   246 Mbits/sec  528   62.2 KBytes       
[  5]   8.00-9.00   sec  28.5 MBytes   239 Mbits/sec  570   60.8 KBytes       
[  5]   9.00-10.00  sec  29.1 MBytes   244 Mbits/sec  629   52.3 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bitrate         Retr
[  5]   0.00-10.00  sec   274 MBytes   230 Mbits/sec  4833             sender
[  5]   0.00-10.04  sec   273 MBytes   228 Mbits/sec                  receiver
7

On the RPi 3 the USB ports share the same bus with the network port, you will never reach full USB speed when the network is active

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8

And probably especially when the network connection is happening via one of the USB ports.