Ive run into an issue that I cant quite seem to understand.
I have 3 hypervisors that are configured to connect to two different iSCSI storage devices (10.255.1/2.6 and 10.255.1/2.8) using multipathing. The hosts and the storage devices are connected to an isolated switch. The switch has two vlans, 20 and 21, for the above subnets. The storage qnaps have interfaces assigned with appropriate addresses for their vlans, as listed above. The problem I am encountering is two of the three hosts have been able to connect via dynamic targets, to the second storage device, 10.255.1/2.8, but cannot seem to connect to the second, 10.255.1/2.6. The third host cannot connect to either. Ive tried pinging from the hosts to both storage devices, pings reply. Hosts can ping each other. SVI interfaces on the switch are configured and pingable from the host as well. So all hosts can ping each others vmkernels, all hosts can ping the gateway (the switch vlan SVI's, and all hosts can ping both adapters on both storage devices. MTU for everything is set to 9000. What am I missing?
Can you explain why you dedicated two separate VLAN IDs (20,21) for the iSCSI traffic? Is there any special consideration for such as this config? or you can ignore them and make it simpler via putting the QNAP and all hosts inside a single VLAN!
First of all try this: If you remove the initiators of 1st & 2nd hosts, and just map the 3rd one, then is the problem still persist?
Can you check your solution with MTU size 1500, not Jumbo Frame?