Have you ever encountered a duplicated ping when you try to ping the iSCSI PortGroups or pinging the ESX Host Itself from vCenter?
In my case I have this issue when I try to ping from ESXi5.0 host to an iSCSI Target.
SAN Storage Configuration:
IBM DS3512 with two Controllers, each with 4 iSCSI Ports.
When I try to ping each of the iSCSI Ports IP Address, I got
64 bytes from xxx.xxx.xxx.xxx: icmp_seq=4 ttl=128 time=0.xxx ms (DUP!)
ESX iSCSI Configuration:
vSwitch with 4 VMKernels PortGroup for iSCSI.
By default, vSwitch will take Route Based on the Originating port ID.
I resolved this issue by:
Changing from Route based on the Originating Port ID to Route based on IP Hash. And I set each VMKernel Port active on one nic only instead of two “Default”
VMNIC3 active for iSCSI-30 and iSCSI-40 because this NIC connected to Switch-1 as well as both iSCSI Ports.
VMNIC9 active for iSCSI-50 and iSCSI-60 because this NIC connected to Switch-2 as well as both iSCSI Ports.
(DUP!) has disappeared after doing this :)