unidirectional slowness
hi,
I am seeing slow file transfers in one direction only to a Windows 2016 server. Both file copy (SMB) and iPerf tests show very similar results. Windows 2022 VM -> Windows 2016 VM (only 2.5Gbps), if I flip the direction and go from Windows 2016 VM -> Windows 202 VM (transfer speed is up to 6.5Gbps). Both VMs have VMXN3 nics with the latest vmware tools and nic drivers (1.9.14.0)
When looking at a trace file from a SLOW (2.5Gbps) transfer, there are intervals of 100s of DUP ACKs (all of them have SACKs), I am not sure if I should be seeing them on a low latency network. [RTT to ACK the segment was: 0.000196000] [iRTT 0.000395000]. Any why only in one direction?
Wireshark capture is split in multiple parts, here is the graph of the first 2 second part. Looking for suggestions / recommendations on what to check next?
Thank you very much.
this was the case where wireshark was showing the results of OS tweaks but not pinpointing to what exactly was changed.
after setting the following parameters back to the defaults, 10Gbps was achievable in both direction
-Smb2CreditsMin -Smb2CreditsMax -DurableHandleV2TimeoutSeconds