Minimal Nested vCenter 6 Lab – Configuring the iSCSI Network

vMotion was pretty easy to configure, we just created a VMkernel port group, specified that i would be used for vMotion traffic and assigned an IP address to it.

However, the trick is on the iSCSI configuration, where two VMMkernel ports need to be created on each host. For the sake of redundancy, each VMkernel port will have one active vmnic and another non used vmnic. This is way to have redundant paths to our iSCSI Target, and this is also the only configuration supported by VMware.

Just a reminder, let’s have another look on how our ESXi vmnics and their uses


In our case, a new standard vSwitch will be created where along with two VMKernel ports, let’s name them iSCSI-A and iSCSI-B, that will be used for iSCSI traffic.

iSCSI-A will have vmnic4 as active interface and vminic5 as non used interface.

iSCSI-B will have vmnic5 as active interface and vminic4 as non used interface.

Name vmnic4 vmnic5 Type IP
iSCSI-A active non used VMKernel
iSCSI-B non used active VMKernel


Basically, we’ll need to do proceed in three different steps

  • Creating the iSCSI VMkernel ports
  • Creating an iSCSI software adapter.
  • Mapping the iSCSI VMkernel port to the iSCSI software adapter.

Let’s get started!

Creating iSCSI VMkernel ports

Go to the first host > Manage > Networking > Virtual Switching > Add host networking



Choose VMkernel Network Adapter


iSCSI will be created in a nws standard vSwitch


On the vSwitch, both vmnic4 and vminc5 will be used. We will customize later the port groups to use one vmnic for each one of them

vCenterLab-iSCSINetwork Confirm your selection and click on Next


Let’s name the first port group iSCSI-A and assign it an IP address of



Confirm your settings and click on Finish to create your first iSCSI port group


iSCSI-A is now created in a new standard vSwitch called vSwitch2, but it is currently using both vminic4 and vmnic5 as active.

vCenterLab-iSCSINetwork Let’s make it use only vmnic4.


Done for iSCSI-A, which is now using only vmnic4 as used adapter.

We know what is left to do now. We need to follow the same steps to create iSCSI-B, and this one will be in vSwitch2, will use an IP of and will use only vminic5 as the active adapter.

Once done, we’ll have something similar to this


ESX1 is now configured and now the second host needs to be configured with the following values, so follow the same procedure for iSCSI configuration in ESX2.

Name vmnic4 vmnic5 Type IP
iSCSI-A active non used VMKernel
iSCSI-B non used active VMKernel


Once everything is done, we’ll have to create a iSCSI adapter. an iSCSI adapter can either be physical (aka Hardware adapter) or virtual (aka Software adapter), and the difference between the two is pretty obvious. You’ll use a Hardware adapter when you have an availHowever, there are some pros and cons of using one instead of the other. For example, when using a Hardware adapter, all of the overhead associated with iSCSI is performed by the iSCSI HBA instead of server resources. On the other hand, when using a Software adapter, the only hardware the server requires is a networking card. I have cited here only one difference between the two, but the list can be long and you’ll want to check the best method to use depending on your environment and your needs.

Anyway, in this example, and because our ESXi host is a virtual machine running in a nested environment, we’ll have be using a Software iSCSI adapter.

Creating the iSCSI Software Adapter

Go to the first host > Manage > Storage > Storage Adapters and add a Software iSCSI adapter



As the above prompt is advising, we need to map the iSCSI VMkernel ports to the Software iSCSI adapter. It is a way of assigning IP addresses to it.

Mapping the VMkernel Ports to the iSCSI Adapter

Select your newly created iSCSI adapter, then go to Network Port Binding

vCenterLab-iSCSINetwork Select both VMkernel port groups created previously for iSCSI use

If for some reason you’re not able to see the iSCSI VMkernel adapter, make sure they are properly configured to use only one active vmnic


You’ll be asked to do a rescan, so proceed accordingly


The iSCSI network configuration is now done, in the next post we will install and configure the iSCSI Target Server in the DC server.

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