Very slow file services on Windows 2008 R2

If your Windows 2008 R2 file server performs too badly (response time in tens of seconds or minutes!), you may try to turn off TCP offloading. Our setup had a virtual 2008 server run by a Citrix XenServer hypervisor using a NetApp NAS appliance as virtual storage. Our raw disk tests showed no performance penalty related to hypervisor/NAS systems. However, response times regarding to access to shared disks were terrible (5 min to start an application!). We have applied Service Pack 1 and all file services related post-SP1 patches available without observing any improvement.

As a last resort, after a tips on TechNet forums, we've turned off TCP offloading by applying following registry changes (reboot is required!):

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters


Value =DisableTaskOffload

Type = DWORD

Data = 1

Value =EnableTCPChimney

Type = DWORD

Data = 0

Value =EnableTCPA

Type = DWORD

Data = 0

Value =EnableRSS 

Type = DWORD

Data = 0