[Samba] NAS with Samba and Multi-TT USB Hubs

[Jeremy Allison]

On Mon, Dec 09, 2019 at 01:40:47PM +0000, Florian Moser | CAC via samba wrote:
> Dear Sir or Madam,
> 
> 
> I've a very specific question about samba...
> 
> My setup: I've a Raspberry 3B with Raspbian and a multi-TT USB hub attached to it. A few full-speed (1MB/s) mass-storage devices are going to be connected to this hub. On every device is just one big file (f.e. 50MB .txt file).
> Multi-TT just helps reading more full-speed devices on a single hub simultaneously. This works perfectly on the local Raspbian system.
> I've plugged in one device to the USB hub and tested the speed = 227kB/s
> Two devices on the same hub at the same time, speed for each hub = 227kB/s
> This also works with three devices or more.
> 
> Now I've set up a samba server on this Raspberry Pi with the directory of the USB-mounting point to be shared on a local network. (NAS)
> The samba server access works with Windows and I see every USB mass-storage as folder in a network directory (as expected).
> The only problem is, that it does not copy the files simultaneously. It copied file by file, so it takes much longer, than copying simultaneously in the local directories of the raspberry.
> 
> F.e. I've four devices connected to the hub. On each device is just a single 50MB file.
> If I copy the whole content of just one device to a local directory (/home/pi/test) it takes about four minutes (~200kB/s)
> If I copy the whole content of all four devices to a local directory at the same time it takes also four minutes because of the multi-TT hub. (With a single-tt hub it would take 16 minutes)
> If I copy the whole content of all four devices with a Windows PC, using the samba server on the raspberry pi, it takes about 16 minutes. (I expected it to take 4 minutes, too)
> 
> Is there a possibility to tell samba or raspbian to copy the contents simultaneously using the multi-TT usb hubs?

This is client driven, not server-driven. So you need
to use a client that will do the simultaneous copy
requests.