Alex Seleznyov's questions

Issue: File of few gigabytes of size (i.e. Debian DVD ISO) gets corrupted when downloadeded using curl or wget to a Windows share from Alpine Linux running in Hyper-V on the same machine Setup:

• Dell T20, Xeon and 32GB RAM
• Windows Server 2016 w/latest patches, etc
• Alpine 3.20 running in Hyper-V
• 10GB Virtual switch, MTU 1500, exposed to both WS2016 and Alpine
• Windows share mounted in Alpine in /etc/fstab

Tests I've run:

• curl/wget in Alpine, save to share - sha256 run on Alpine differs from expected. Multiple runs gets different sha256.
• curl in Windows, save to local disk - sha256 run on Alpine matches expected value

Created a new VM with empty disk, installed Alpine 3.20 with latest patches, and got the same behaviour.

Run out of ideas where to look and what to check so any idea will be greatly appreciated.

I have a Xeon-based Dell T20 with Quad Intel I350 running Windows Server 2016 Hyper-V with OpenSUSE as Gen2 VM. Both Windows Server and OpenSUSE have dedicated ports on I350, no sharing. SR-IOV is enabled on all NIC's ports and Hyper-V virtual switch as well. VMQ is enabled, all offload options are enabled, no jumbo frames, no VLAN set but VLANs are enabled. EEE is disabled.

The problem is, when I run iperf3 from another box to Windows Server, I get 940MBit/s on average both ways, and when iperf3 is running against OpenSUSE VM, throughput never goes above 130MBit/s regardless of direction.

No CPU spikes during test thus I assume the problem is not a lack of CPU power.

Is those 130 MBit/s is the greatest speed I can get to/from VM?

Update 1: Switch Properties:

Name                                : LanIOV
Id                                  : 881379d9-2030-4a08-8594-2f3001ee2a55
Notes                               : 
Extensions                          : {Microsoft Windows Filtering Platform, Microsoft Azure VFP Switch Extension, Micr
                                  osoft NDIS Capture}
BandwidthReservationMode            : None
PacketDirectEnabled                 : False
EmbeddedTeamingEnabled              : False
IovEnabled                          : True
SwitchType                          : External
AllowManagementOS                   : False
NetAdapterInterfaceDescription      : Intel(R) Ethernet Server Adapter I350-    T4 #4
NetAdapterInterfaceDescriptions     : {Intel(R) Ethernet Server Adapter     I350-T4 #4}
IovSupport                          : False
IovSupportReasons                   : {SR-IOV cannot be used on this system as the PCI Express hardware does not suppor
                                      t Access Control Services (ACS) at any root port. Contact your system vendor for 
                                      further information., SR-IOV cannot be used on this network adapter as the PCI Ex
                                      press hardware does not support Access Control Services (ACS). This device may wo
                                      rk in an alternate PCI Express slot. Contact your hardware vendor for further inf
                                      ormation.}
AvailableIPSecSA                    : 0
NumberIPSecSAAllocated              : 0
AvailableVMQueues                   : 7
NumberVmqAllocated                  : 3
IovQueuePairCount                   : 0
IovQueuePairsInUse                  : 0
IovVirtualFunctionCount             : 0
IovVirtualFunctionsInUse            : 0
PacketDirectInUse                   : False
DefaultQueueVrssEnabledRequested    : True
DefaultQueueVrssEnabled             : True
DefaultQueueVmmqEnabledRequested    : False
DefaultQueueVmmqEnabled             : False
DefaultQueueVmmqQueuePairsRequested : 16
DefaultQueueVmmqQueuePairs          : 4
BandwidthPercentage                 : 0
DefaultFlowMinimumBandwidthAbsolute : 0
DefaultFlowMinimumBandwidthWeight   : 0
CimSession                          : CimSession: .
ComputerName                        : SERVER
IsDeleted                           : False