Quick query here.
I have a RPi4 with a drive attached and this is used as the media server for my two Vero’s.
It used to be a ext4 formatted mechanical HDD, and with a sata to USB3 converter I was getting transfer speeds from my PC to the network drive up to 80+MB/s. I didn’t get that speed all the time, it was often slower, but typically 50-60MB/s was the norm, with 80+ not being that uncommon and similarly 30-40 also not being unheard of. I figure it depends on the specific part of the spinning disk it was writing to.
Anyway, after many years of use the drive started to die, so I replaced it with a Samsung SSD.
However, transfer speeds have been worse to it than to the mechanical spinner HDD. It is formatted ext4 as well, and got a clean copy of the media from a backup rather than from the dying drive.
Transfer speeds are a pretty standard 33MB/s, with it creeping up to high 30s sometimes, and dropping down to mid-twenties frequently too.
Iperf3 between the RPi4 and desktop are typically in the 700-800Mbps range.
What I’ve tested:
dd if=<large file> of=/dev/null bs=4M 471+1 records in 471+1 records out 1977998862 bytes (2.0 GB, 1.8 GiB) copied, 7.80134 s, 254 MB/s
I then tried:
dd if=/dev/zero of=<file on SATA disk> bs=4M count=100
But got a permissions error: “Failed to open : Permission denied”
Given that it is an SSD, I would like to think there are no writing speed issues, but I just don’t understand why the writing speed is generally slower compared to my old mechanical HDD!