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Showing posts from June, 2014

NFS storage and ESXi 5.5 TCP delayed ack

By default the behavior of ESXi 5.5 is to have TCP  delayed_ack  set to 1  It caused some performance issues related to latency between the ESXi host and our NFS storage. We need to change the behavior by setting the value to 0 , so that latency issues are solved. vsish -e set /net/tcpip/instances/defaultTcpipStack/sysctl/_net_inet_tcp_delayed_ack 0 In order too ensure that delayed _ack is disabled across reboots we need to edit /etc/rc.local.d/local.sh and add the following line in there. vsish -e set /net/tcpip/instances/defaultTcpipStack/sysctl/_net_inet_tcp_delayed_ack 0 Hope this helps.