Hey Clemens, thank you for your response. Here is a little update:
We got ourselves a Netgear 10gb switch and two of those cheap 10gb Asus gaming NIC's. The first idea was to use Truenas (aka Freenas) as a new Server but reading the forums it seemed that the Asus NIC's are not yet properly supported. After a little search we dicided to try Unraid NAS Software.
We took one of our older rendernodes and installed the Asus NIC together with the Unraid Software. The NIC was instantly recognized by the OS and after a quick setup the server was already usable.
And it works great. I didn't finish the finetuning yet but I get stable ~1,1 Gbyte/s transfers on bigger files and around 200-500Mbyte/s on small files.
I also can't say much about the stability yet but working on it seems great too. Project opening, saving times, render start all seemed to be as fast as doing it locally. The measured times of render start and IR start until first pass were even faster than local.
The next step once I'am back in the office will be ordering a proper dual port NIC for the server and couple more Asus NIC's for the clients, along with a bunch of server type SSD's.
Can somebody give some insight if there is a dire need for server memory to have ECC feature in or kind of business? Any ideas on SSD's for the server?
Thanks