I've recently hooked up an ext4 formatted external USB3.0 harddrive to my Raspberri PI 4 (USB3.0 slot) and shared it in my network using Samba. The first upload to the drive went smoothly, but every upload afterwards has been at a terribly low transfer speed of ~500KB/s. Both devices are connected to the network over Wifi, but my Unifi gateway shows only a 4% utilization.

Transfer speed

I've checked my network usage on both my Windows laptop and my Raspberry Pi, nothing too outrageous there it seems.

Network usage

It also seemed to bog down my SSH terminal, but again, a top on the Pi did not show any sort of excessive CPU usage (average CPU load of 25%).

I've also shut down the Plex and Windscribe services to no avail, in the hopes that it might have been the Plex File Watcher throttling traffic or my VPN inexplicably slowing down network traffic.

  • I have found a possible duplicate here which seems to place the bottleneck with Samba over Wifi I did a quick test, hooking up my PI with an ethernet cable. I started transmitting at speeds of about 15MB/sec, but quickly dropped to a more stable (yet still rather slow) speed of ~5MB/s. So it looks like I'll have to keep my Pi hooked up to the network via UTP. – Pieter Helsen Jun 19 '20 at 13:12
  • do you have many neighbours with wifi on or near the same channel you use? Also, can you confirm the drive is really USB3.0? look in lsusb -t ... can you see your drive with values like Class=Mass Storage, Driver=uas, 5000M – Jaromanda X Jun 19 '20 at 13:23
  • 1
    "Average CPU load of 25%" on a quad core machine could (and most likely does) mean one core is running at 100%. You should check that with something that shows all four (eg. htop). A long running process that can spread it's load over multiple thread usually will, but in many contexts this isn't possible. Point being, if samba is working one core 100% processing is the bottleneck. It can't max out more than one (= 25% total load) if the work it is doing can't or isn't parallelized by the application. – goldilocks Jun 19 '20 at 13:50

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.