Windows 10 Samba sharing slow/lagging problem

Question

I've an application named daemon the launch some other applications using a network share folder as source for its self and the other applications, Typically I've 1 PC running Win10 and other 2 still running win7, the daemon application and the other applications are stored in Win10 PC and its folder is shared to everyone so that any other PC in the same network can access and run these executables.
On the others Win7 PC I start the daemon through the network share and then those daemon when received through TCP a start command they start to launch using a CreateProcess some other application using as source folder the same network shared used by daemon to be launched, in others words all the executable are remoted on WIN 10 PC, the 2 WIN 7 PCs doesn't have any executable on local drives.
The strange thing that happens is that more or less randomly some executables take 30 seconds and more to start their execution, sometimes you see the console but for 30 seconds the executable is not yet running, the main function is not still been called, moreover if I analyze the samba traffic with wireshark in these seconds it is as if everything were stopped 0 samba packets exchanged between the 2 PCs, as if it were all freezing.
keep in mind the every executable launched opens files that reside on the same network share, so is another samba request during execution, in fact sometimes the executables block when an open file is called...

This doesn't happens if like "repository" I use another WIN7 PC....
i can't understand what's going on and why samba seems to be blocked
All the applications are builded using VS2015 and are all console application

Answer 1

Hello Stefano,

You mention "Samba" (https://it.wikipedia.org/wiki/Samba_(software)) in your message, but this might just be a misunderstanding of the name - Samba is an implementation of the SMB protocol used by non-Windows systems. All of the systems in your set-up seem to be running various versions of Windows.

Such long delays (30 seconds) are probably due to waiting for "some" response from the network, but not necessarily just SMB traffic (on TCP port 445) - it might be something to do with DNS, DFS, or many other things.

The first thing that I would do would be to capture all network traffic from the client when an application is about to start, without using any capture filters or preconceptions about what might be happening and then try to understand the captured traffic once an example of a long delay has been captured.

Gary