Slow upload to RT-AC68U USB Disk via VPN

[djphilosophy]

RT-AC68U with MerlinWRT 384.8_2

I occasionally connect remotely via OpenVPN to my RT-AC68U at home to upload files to the attached disk (on the USB3 port, USB3 2TB disk). I just tried uploading a file.

• The fastest upload speed I was able to attain was 550KB/s (~4.3 Mbps) using FTP.
• Tried both SMB and upload using the AiCloud function: both were even slower (less than half the above speed).
• The connection I'm on tests with an upload speed over 40 Mbps. Download speed on the RT-AC68U side is over 200 Mbps.
• Watching the CPU levels while uploading via FTP, average was around 20%.
• QoS is off. AiProtection is off.
• Not using any custom scripts. Did a factory reset last time I upgraded to this version of MerlinWRT.

Any suggestions as to why the upload speed is so slow, especially given that the CPU isn't even close to being maxed out?

 

[eibgrad]

I would eliminate the USB drive for the moment and test the raw speed, perhaps using iperf (it can test the data in both directions). Just to get a baseline on what's possible. Then work from there. Otherwise you could end up on a wild goose chase.

 

[djphilosophy]

I would eliminate the USB drive for the moment and test the raw speed, perhaps using iperf (it can test the data in both directions). Just to get a baseline on what's possible. Then work from there. Otherwise you could end up on a wild goose chase.

Is iperf included in MerlinWRT? If it's optware I don't think I want to mess with installing that now. I do know that from previous speed tests through the VPN I wasn't impressed with the speed, I think never getting more than 5 Mbps download on my end (upload on the RT-AC68U side is 12 Mbps). I can't get an accurate speed test result right now because I'm at an IPv6 address, and for some reason, even though I'm connected through the VPN, when I'm at an IPv6 address the VPN is essentially ignored and the data goes direct to the speed test sites (another issue entirely).

 

[eibgrad]

I have the same router (RT-AC68U). I only get about 10-20% efficiency when the VPN is enabled.

Yeah, I just checked, and no iperf. Kind of surprised they didn't bother to include it given how useful it can be for performance analysis. This is a perfect example.

Btw, most tomato firmware (and Merlin is a tomato variant) include a script to install Entware, so it's not like you have to start digging around to figure it all out.

/usr/sbin/entware-setup.sh

This is one of those niceties about using tomato-based firmware.

 

[L&LD]

In addition to @eibgrad's excellent suggestions, I would also recommend you to consider the amtm + scripts route too (which includes Entware, Optware has been outdated for a long time now).

amtm Step-by-Step https://www.snbforums.com/threads/amtm-step-by-step-install-guide-l-ld.56237/#post-483421

 

[RMerlin]

Yeah, I just checked, and no iperf. Kind of surprised they didn't bother to include it given how useful it can be for performance analysis. This is a perfect example.

I don't include it because it would be unnecessary bloat (it can be installed through Entware for the 0.05% of users that might need it), and also because running iperf on the router will provided skewed results, as the router's CPU might become the bottleneck then. Iperf itself on a 800 MHz RT-AC68U will generate a very high CPU usage on its own, which might result in slowing down routing performance.

 

[djphilosophy]

I have the same router (RT-AC68U). I only get about 10-20% efficiency when the VPN is enabled.

I wonder what the bottleneck is since the CPU is barely taking a hit. Regardless, if it's a known issue with this router, I won't bother installing iperf.

Strange that uploading via AiCloud (no VPN) was even slower.

 

[eibgrad]

I wonder what the bottleneck is since the CPU is barely taking a hit. Regardless, if it's a known issue with this router, I won't bother installing iperf.

Strange that uploading via AiCloud (no VPN) was even slower.

My current running theory.

https://www.snbforums.com/threads/e...figuration-in-asus-routers.46341/#post-482239