Why is the LAN transfer speed too slow?

Question

ubuntu

On board the working machine ubuntu 18.04
On board the server (mediocre nontop, years of commercials 2012. I can’t find more specific information on it) with Ubuntu 16.04.
The essence of the problem is as follows.
The working machine, the server and other other devices hang in one local area network.
There is a file, for example on 10 Gb.
In a network only the working computer and the server are alive.
The network folder on the server is shared and connected on the working machine through mount.cifs.
I turn on the copying of the same file in 10 GB to the server, and the system shows that the file will be copied ... 1 hour 30 minutes. The question is, why is it taking so long?
The screw on the server (1TB) is very smart.
Screw on the working machine (WD from the "hot" class).
Network 100Mb.
By running the same procedure from a neighboring screw (toshiba) with windows 10 on board, the same procedure takes several orders of magnitude less time. No more than 20 minutes, maybe even less.
It was a matter of connecting an external hard drive via usb 2.0.
A file weighing 8 GB was copied to it in the same way for 40 minutes. From which we can say that the matter is clearly not in the network, but in the system itself.
ps file manager in Nautilus system, and its "progress bar" shows that the copy speed is going to (3.0 MB/sec). Which is a blatant lie and is not reality.
Pss I don’t know which way to dig, Googleyandex did not give any help, because the problem with writing to a USB flash drive prevails.
Psss did not try to do it through the terminal mv command, but there is a suspicion that the result will be the same
pssss 10GB occupies not 1 file, but 11. It is copied by the whole directory. The same problem happens with other files. I started copying a node.js project, in which a very large node_modules directory was copied for an unacceptably long time...

Answer 1

Everything is fine with the network, it's CIFS that slows it down. Try to measure it with SSH/NFS or iperf.