SFTP uploads to same server very slow on one computer
December 12, 2024 9:01 AM Subscribe
There's an ftp server that I upload to frequently that is very slow on my desktop computer, but normal speeds when on my laptop. I'm using filezilla. What's going on and how can I fix it?
Computer 1 (slow): Desktop, windows 10, ethernet connection. Upload speed around 300kb/s
Computer 2 (fast): Laptop, windows 11, wifi connection. Upload speed around 10mb/s
The server in question is an SFTP server and I'm using the same credentials from both computers. I'm transferring jpg files.
The filezilla settings (including this particular server info) were exported from Computer 1 when I set up Computer 2, so they are the same on both. The slowness on the desktop has occurred in two different houses (it's been going on for a couple years!). I upload to other servers pretty often, as well, and on Computer 1, I regularly get between 10mb/s and 20mb/s if not faster. It's only this one server that has the issue, and only from Computer 1.
Ping times to the server are the same on both computers.
Yesterday I was uploading from both computers at the same time and Computer 1 started around 2mb/s and then quickly settled around 300kb/s for the remainder of the queue. Computer 2 was transferring files so quickly I couldn't see the speed. In the time it took me to transfer 100 files from Computer 1, I transferred more than 700 from Computer 2. Both computers were within arm's reach in the same room.
It's been driving me crazy....what can I check to get this figured out?
Computer 1 (slow): Desktop, windows 10, ethernet connection. Upload speed around 300kb/s
Computer 2 (fast): Laptop, windows 11, wifi connection. Upload speed around 10mb/s
The server in question is an SFTP server and I'm using the same credentials from both computers. I'm transferring jpg files.
The filezilla settings (including this particular server info) were exported from Computer 1 when I set up Computer 2, so they are the same on both. The slowness on the desktop has occurred in two different houses (it's been going on for a couple years!). I upload to other servers pretty often, as well, and on Computer 1, I regularly get between 10mb/s and 20mb/s if not faster. It's only this one server that has the issue, and only from Computer 1.
Ping times to the server are the same on both computers.
Yesterday I was uploading from both computers at the same time and Computer 1 started around 2mb/s and then quickly settled around 300kb/s for the remainder of the queue. Computer 2 was transferring files so quickly I couldn't see the speed. In the time it took me to transfer 100 files from Computer 1, I transferred more than 700 from Computer 2. Both computers were within arm's reach in the same room.
It's been driving me crazy....what can I check to get this figured out?
Are the clients running different versions of FileZilla (or the underlying operating system), and thus using different ciphers?
Is the server on the same network as your two computers, or remote? (Just thinking about what the network path is here, and if maybe your old desktop is taking a longer path through an old switch or something.)
posted by wenestvedt at 9:11 AM on December 12 [1 favorite]
Is the server on the same network as your two computers, or remote? (Just thinking about what the network path is here, and if maybe your old desktop is taking a longer path through an old switch or something.)
posted by wenestvedt at 9:11 AM on December 12 [1 favorite]
Response by poster: The server is remote. All other remote servers do not have this slowness issue.
Filezilla versions:
Computer 1 - 3.66.5
Computer 2 - 3.67.1
Operating systems are Windows 10 (slow uploads) and 11.
The slowness has persisted for a couple of years, so over the course of many versions of Filezilla. I update periodically on both computers whenever the the "new version" screen gets annoying enough and I'm not uploading on a deadline.
posted by msbrauer at 9:26 AM on December 12
Filezilla versions:
Computer 1 - 3.66.5
Computer 2 - 3.67.1
Operating systems are Windows 10 (slow uploads) and 11.
The slowness has persisted for a couple of years, so over the course of many versions of Filezilla. I update periodically on both computers whenever the the "new version" screen gets annoying enough and I'm not uploading on a deadline.
posted by msbrauer at 9:26 AM on December 12
FileZilla *does* have a "speed limit" option (Transfer -> Speed Limits) so I'd first make sure that's not enabled somehow.
Is the slow PC still slow if you use a different network interface (wifi, or a USB ethernet adapter -- be sure to unplug the usual Ethernet)? If it's still slow, that would rule out a weird networking issue, at least. If this fixes it, it could be a QoS feature or similar on your router causing the trouble, which could explain why the issue followed you between houses. (New interface = new MAC address = the router doesn't know it's the same PC.)
(QoS = Quality of Service = the router slows down some traffic to let other traffic go faster. Typically this is used to speed up the Web, so non-Web traffic like FTP is de-prioritized.)
posted by neckro23 at 9:26 AM on December 12
Is the slow PC still slow if you use a different network interface (wifi, or a USB ethernet adapter -- be sure to unplug the usual Ethernet)? If it's still slow, that would rule out a weird networking issue, at least. If this fixes it, it could be a QoS feature or similar on your router causing the trouble, which could explain why the issue followed you between houses. (New interface = new MAC address = the router doesn't know it's the same PC.)
(QoS = Quality of Service = the router slows down some traffic to let other traffic go faster. Typically this is used to speed up the Web, so non-Web traffic like FTP is de-prioritized.)
posted by neckro23 at 9:26 AM on December 12
Response by poster: FileZilla *does* have a "speed limit" option (Transfer -> Speed Limits) so I'd first make sure that's not enabled somehow.
Not enabled. All other servers I upload to go full speed.
Is the slow PC still slow if you use a different network interface (wifi, or a USB ethernet adapter...
I just unplugged the ethernet and switched to wifi for 35 files and it started around 1.7mb/s for the first few seconds and then quickly slowed down to around 200kb/s. Midway through the upload queue, the transfer speed went up to about 500kb/s for about 30 seconds, and then back around 200-300kb/s.
Midway through the queue, I paused and uploaded a few of the same files to a different remote server and the files went super fast (so fast I couldn't see the speed).
posted by msbrauer at 9:47 AM on December 12
Not enabled. All other servers I upload to go full speed.
Is the slow PC still slow if you use a different network interface (wifi, or a USB ethernet adapter...
I just unplugged the ethernet and switched to wifi for 35 files and it started around 1.7mb/s for the first few seconds and then quickly slowed down to around 200kb/s. Midway through the upload queue, the transfer speed went up to about 500kb/s for about 30 seconds, and then back around 200-300kb/s.
Midway through the queue, I paused and uploaded a few of the same files to a different remote server and the files went super fast (so fast I couldn't see the speed).
posted by msbrauer at 9:47 AM on December 12
Not really my wheel house, but does the tracert command show differences for desktop and laptop, when run during or before the upload? Anyone with more network experience can squash this suggestion if it is not relevant.
posted by forthright at 10:52 AM on December 12 [1 favorite]
posted by forthright at 10:52 AM on December 12 [1 favorite]
Check your MTU size on both devices and the router, if the MTU size on one machine is smaller then the one on the router’s connection to the external networok those packets will go through efficiently. If one is larger those will get slowed down because they will have to be split, which a) takes more work and b) generates more response acknowledgement packets.
See for example: https://www.thewindowsclub.com/how-to-change-mtu-on-windows
posted by tiamat at 11:49 AM on December 12 [2 favorites]
See for example: https://www.thewindowsclub.com/how-to-change-mtu-on-windows
posted by tiamat at 11:49 AM on December 12 [2 favorites]
Maybe not a network issue, but a file fetching issue? What kind of storage are you reading the files from? HDD or SSD? What sort of interface to those: SATA, M.2 or whatever it is for SSDs on a card, USB (and if USB - 2.0 or 3.1 or 3.2)? You can't send the files any faster than you can read them from storage
posted by TimHare at 11:50 AM on December 12 [1 favorite]
posted by TimHare at 11:50 AM on December 12 [1 favorite]
Is your desktop Win10 PC pretty old? I wonder if it's got a slower network card (Fast Ethernet at 100mb) than some fancy new WiFi6 in the laptop, or something.
posted by wenestvedt at 11:50 AM on December 12
posted by wenestvedt at 11:50 AM on December 12
Is Windows 10 hogging all the bandwidth for updates? That’s often it for me. (I do understand up vs down, but Windows can also just be so weird so regularly.)
posted by lokta at 12:31 PM on December 12
posted by lokta at 12:31 PM on December 12
Response by poster: MTU numbers are the same on both computers.
Not a file fetching error because the same files transfer quickly to other SFTP servers.
Not a network card issue since, again, I can transfer at full speed to any other server on the slow machine.
posted by msbrauer at 12:31 PM on December 12
Not a file fetching error because the same files transfer quickly to other SFTP servers.
Not a network card issue since, again, I can transfer at full speed to any other server on the slow machine.
posted by msbrauer at 12:31 PM on December 12
Dang, this must be the SFTP (SSH) connection, then, if it's just the one computer and the one host. If I wanted to really get to the bottom of this, I would look into what ciphers are proffered in which order.
posted by wenestvedt at 12:39 PM on December 12
posted by wenestvedt at 12:39 PM on December 12
Response by poster: I would look into what ciphers are proffered in which order
Could you explain this a little? What am I looking at and how might I look at it?
posted by msbrauer at 1:24 PM on December 12
Could you explain this a little? What am I looking at and how might I look at it?
posted by msbrauer at 1:24 PM on December 12
As a simpler test, I’d connect directly to the server with an Ethernet cable (assuming it is on site). That eliminates a bunch of variables.
posted by Gilgamesh's Chauffeur at 1:29 PM on December 12 [1 favorite]
posted by Gilgamesh's Chauffeur at 1:29 PM on December 12 [1 favorite]
Response by poster: The remote server is not on site. I have no way to connect to it directly.
posted by msbrauer at 4:56 PM on December 12
posted by msbrauer at 4:56 PM on December 12
If it were me, I'd get a Wireshark capture of the slow one and see if anything unusual stands out. The transfer is encrypted so you can't see the data, but things like packet loss aka retransmit will be visible. Or you may see higher round trip times that you can dig into further.
Aging network cards can start to flake in unusual ways, for me there were certain sites that wouldn't load even as others were fine.
posted by Horselover Fat at 5:44 PM on December 12 [1 favorite]
Aging network cards can start to flake in unusual ways, for me there were certain sites that wouldn't load even as others were fine.
posted by Horselover Fat at 5:44 PM on December 12 [1 favorite]
Some ideas:
1. FileZilla / Site Manager / Site / Transfer Settings has a setting called "Limit number of simultaneous connections". If this were set to a low number, and the SFTP server is rate-limiting by connection, this could explain your problems.
2. FileZilla / Settings / Connection/FTP/FTP Proxy - if you have one set, it could slow things down.
3. FileZilla/Settings/Transfers/Enable Speed Limits - already mentioned above.
4. I can't remember if SFTP uses active / passive modes? Perhaps that's relevant.
5. FileZilla/Settings/Logging - enable this, and also set FileZilla/Settings/Debug - set to level Four. Maybe you'll see something interesting in the log file?
posted by soylent00FF00 at 7:50 AM on December 13
1. FileZilla / Site Manager / Site / Transfer Settings has a setting called "Limit number of simultaneous connections". If this were set to a low number, and the SFTP server is rate-limiting by connection, this could explain your problems.
2. FileZilla / Settings / Connection/FTP/FTP Proxy - if you have one set, it could slow things down.
3. FileZilla/Settings/Transfers/Enable Speed Limits - already mentioned above.
4. I can't remember if SFTP uses active / passive modes? Perhaps that's relevant.
5. FileZilla/Settings/Logging - enable this, and also set FileZilla/Settings/Debug - set to level Four. Maybe you'll see something interesting in the log file?
posted by soylent00FF00 at 7:50 AM on December 13
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posted by msbrauer at 9:03 AM on December 12