new Thinkpad install - ssh stalling on big files

cbrace

Well-Known Member

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Messages: 258

#1
Hi all,

After using FreeBSD on the server for many years, I've made my first excursion into FreeBSD on the desktop. I've got it running now on a second-hand Lenovo x220. I installed v12 RC3 following the instructions of vermaden here:
Now (in FreeBSD 12.x) it is possible to install FreeBSD on GELI encrypted root on ZFS pool without any additional partitions or filesystems. No longer separate UFS or ZFS boot pool /boot filesystem is needed. And what is even more appealing such setup is supported both on UEFI and BIOS (also refereed as Legacy or CSW) systems. [...]

FreeBSD Desktop – Part 2.1 – Install FreeBSD 12
I've got the mate DE installed and so far so good.
One minor issue:

Copying large files from a remote host, file transfer stalls after around 100MB. No error message, the transfer speed just drops to 0. I don't see this copying lots of small files, only with large ones, like 1GB. This only happens when using an encrypted session, ssh or scp. Using wget or copying via from NFS share, I don't see it. For this reason, I don't think it is the WiFi connection. A search turns up some hits, but mostly indicating a network issue, like MTU, which doesn't seem to be the issue here, since using unencrypted file transfer I hit the full speed of the connection. It seems rather that ssh "chokes" on large files

Any ideas?

Thanks
 

aragats

Aspiring Daemon

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Messages: 942

#3
MTU, which doesn't seem to be the issue here, since using unencrypted file transfer I hit the full speed of the connection. It seems rather that ssh "chokes" on large files
Namely MTU may cause SSH to choke since brakes its packets. I've seen such things a lot. For example, if your ISP hardware uses MTU=1492, and you computer has the default 1500, it will happen.
 

SirDice

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#4
Copying large files from a remote host, file transfer stalls after around 100MB. No error message, the transfer speed just drops to 0.
How remote is the remote system? Is it somewhere on the internet or on the local LAN?
 

VladiBG

Well-Known Member

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Messages: 435

#5
If you copy the file from Windows OS using WinSCP go to Advanced->Connection and uncheck the "Optimze Connection Buffer size".
 
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cbrace

cbrace

Well-Known Member

Thanks: 7
Messages: 258

#6
I'm using WiFi here. The installer recognised the wireless card, so there was no need to plug in a cable.

I've narrowed down the problem somewhat:

It does not happen secure copying to and from another FreeBSD system, either on the LAN or remotely. It happens copying large files to and from two Debian-based desktop systems on the LAN. I can use NFS to move large files around on LAN, no need for encrypted connections, so I have given up trying to determine what is causing the secure file transfers to stall.
 
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