Readynas Duo v2 poor performance on SMB connection

StephenB wrote:
Do you have a windows PC that you can use to test SMB? Also it might be worth doing a direct connection (directly connecting the ethernet cable between the PC and the NAS, and using static addresses to to connect). You don't need a crossover for that, your existing cables will work.

I made different test with this configuration:
- PC with Ubuntu 14.04
- PC with Windows 7 SP1
- PC with Windows 8.1
- Static IP both for PC and NAS
- PC and NAS attached to the same switch, no other component attached
- Test performed with only 2 system connected (PC and NAS)
- SMB oplock mode enabled, no jumbo frame enabled, even it is supported by all components, switch included.

My home LAN is adopting this configuration: fiber router - physical firewall (appliance) - Backbone with a Gigabit Netgear GS105 switch - Netgear GS108GE reserved only to NAS and PC. Any unwanted "interference" should not be present within internal LAN with this configuration.

My concern is about the difference between the two protocol: CIFS perform 3 times better even with Linux desktop where SMB should be considered more efficient.

StephenB wrote:
What model switch are you using? Do you know if it supports 802.3x flow control?

Netgear GS108GE ProSafe Switch, 8 port, Gigabit

http://www.netgear.co.uk/business/products/switches/unmanaged/GS108.aspx#tab-techspecs

No flow control support according to its specification.