I was testing network speed on my Raspberry Pi 4 8GB and there was something strange happening (maybe it is just because I use Raspbian but I was curious if someone can confirm/deny it on their Arch install).
iperf3 gives me solid 1Gbps speed
[ ID] Interval Transfer Bitrate Retr [ 5] 0.00-10.00 sec 1.09 GBytes 939 Mbits/sec 0 sender [ 5] 0.00-10.00 sec 1.09 GBytes 936 Mbits/sec receiver
But when I copy a big file (1GB and then 4GB) I get only about 40 MB/s. It doesn’t matter if it is on external SSD or directly in
/tmp/ (which is mounted as
tmpfs on both devices).
~ >>> scp pi:/tmp/bigfile2 /tmp/ bigfile2 100% 1000MB 40.7MB/s 00:24
the same with
~ >>> rsync -chavP --stats pi:/tmp/bigfile2 /tmp/ receiving incremental file list bigfile2 1.05G 100% 40.93MB/s 0:00:24 (xfr#1, to-chk=0/1) Number of files: 1 (reg: 1) Number of created files: 1 (reg: 1) Number of deleted files: 0 Number of regular files transferred: 1 Total file size: 1.05G bytes Total transferred file size: 1.05G bytes Literal data: 1.05G bytes Matched data: 0 bytes File list size: 67 File list generation time: 6.006 seconds File list transfer time: 0.000 seconds Total bytes sent: 43 Total bytes received: 1.05G sent 43 bytes received 1.05G bytes 34.39M bytes/sec total size is 1.05G speedup is 1.00
The same gives me ~120 MB/s on my spared laptop on the same ethernet cable.
Could this be something hardware or software related?