We are operating some guest OS' (Windows Server 2012 R2 Standard ) on ESXi 5.5U1, and about 150 .NET applications are working on each guest OS.
But, the following error occured intermittently when the .NET application communicate another client.
"An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full."
So, we took actions below, but all failed.
a. TCP parameter modification
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
TcpTimedWaitDelay - 30
MaxUserPort - 65534
TcpNumConnections - 16777214
TcpMaxDataRetransmissions - 5
b. IPv6 disable
c. OS memory extension: 8GB → 16GB
d. NIC change: E1000 → VMXNET3
We would appreciate your help.