Hey everyone! I'm looking for some help with a performance issue I'm experiencing on my SFTP server. I recently set up SFTPGo at work, and while it's meeting our basic needs, I've noticed something concerning. This system isn't heavily used—maybe just five times a month. It's hosted on a fiber connection with 100 Mbps up and down. However, when I attempt to download files from the server, I can't seem to exceed about 8 MB/s, which feels quite low considering my home setup has 1 Gbps up and down fiber.
I've double-checked the firewall configurations and even talked to my ISP, but everything seems fine on that front. The ISP mentioned we hit our bandwidth limit when downloading but didn't offer much detail beyond that. I also checked things like encryption, disk I/O, and CPU usage on the server, and nothing seems to be bottlenecking performance. I'm wondering if I should increase our bandwidth or if it could be something else I haven't thought of. Should I test during off-hours when fewer people are around? Any suggestions or insights would be greatly appreciated—thanks!
3 Answers
You’re actually not far off from what you’d expect. 8 MB/s is roughly 64 Mbps after converting. With some overhead from the protocol, you're hitting almost the max you can expect from a 100 Mbps connection. It's worth testing the speeds when the office is less busy to see if that impacts performance.
Make sure to check your TCP window sizes. For better performance on high-speed connections, you might want to increase those buffers. Sometimes they default to a much smaller size, which can limit speeds significantly. Try setting them to at least 256KB for a start.
It looks like your download speed is about 64 Mbps, which is not surprising given your upload limit. You might be experiencing the expected performance based on the limitations of your connection. Since you have a 100 Mbps shared line, any other activity in the office could also affect your speeds.
I see what you mean! I hadn't considered that the shared line might be affecting the speed. I'll definitely keep an eye on office activity.
Thanks! That makes sense. I’ll try measuring on a quieter day.