SCP stalled most of the time

Help and Support Raspberry Pi
1

Hi there,

since a few years i used SCP for transferring movies to the PI (and now the PI2). I use a EDIMAX EW-7811UN Wifi Dongle on the PI. Now that I use OSMC the SCP transfer does not work. Every time the rate drops and gets stalled after a few minutes. Sometimes rebooting helps and I can transfer one movie! But after some time it does not work, again.

Greetings André

2

You may need a faster SD card. You should also use iperf to check your network connection.

3

My SD card is class 10 and has a write speed of 15-20 MB/s. SCP starts with 3 MB/s. I would be completely okay with that but it drops to almost zero and gets stalled then.

4

Most likely because the SD card is writing back (flushing buffer). If it oscillates in speed, then this would indicate it.

You should also use iperf to check your network connection.

5

Thanks :wink: Ill check the network later. Just want to mention that i am sending directly to a HDD with >30 MB/s. So i think the SD shouldnt be the problem.

6

My iperf3 results: PI is client
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 1.00 MBytes 8.42 Mbits/sec 0 86.3 KBytes
[ 4] 1.00-2.00 sec 1.87 MBytes 15.7 Mbits/sec 0 168 KBytes
[ 4] 2.00-3.00 sec 1.57 MBytes 13.2 Mbits/sec 0 240 KBytes
[ 4] 3.00-4.00 sec 2.11 MBytes 17.7 Mbits/sec 0 307 KBytes
[ 4] 4.00-5.00 sec 1.66 MBytes 13.9 Mbits/sec 0 355 KBytes
[ 4] 5.00-6.00 sec 1.89 MBytes 15.9 Mbits/sec 0 420 KBytes
[ 4] 6.00-7.00 sec 1.48 MBytes 12.4 Mbits/sec 0 420 KBytes
[ 4] 7.00-8.00 sec 1.53 MBytes 12.9 Mbits/sec 0 469 KBytes
[ 4] 8.00-9.00 sec 1.75 MBytes 14.7 Mbits/sec 0 496 KBytes
[ 4] 9.00-10.00 sec 1.55 MBytes 13.0 Mbits/sec 5 243 KBytes

Pi as server
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.15 sec 2.00 MBytes 14.6 Mbits/sec
[ 4] 1.15-2.66 sec 768 KBytes 4.17 Mbits/sec
[ 4] 2.66-3.20 sec 1.00 MBytes 15.3 Mbits/sec
[ 4] 3.20-5.07 sec 128 KBytes 562 Kbits/sec
[ 4] 5.07-5.07 sec 0.00 Bytes 0.00 bits/sec
[ 4] 5.07-6.05 sec 2.50 MBytes 21.5 Mbits/sec
[ 4] 6.05-7.04 sec 2.12 MBytes 18.0 Mbits/sec
[ 4] 7.04-8.79 sec 1.62 MBytes 7.79 Mbits/sec
[ 4] 8.79-9.77 sec 128 KBytes 1.07 Mbits/sec
[ 4] 9.77-10.70 sec 256 KBytes 2.25 Mbits/sec

Looks a bit strange and has some drops too… maybe my wifi adapter is broken or the drivers?

7

when plugin the wifi adapter to the usb hub i get >3,5MB/sec. for now!

8

Well 3h later it started stalling again -.-

9

What is the output of

iwconfig wlan0 | grep Power

instead wlan0 if different place your device