iSCSI Multi Pathing in VMware

Posted by Aruna Lakmal on 8:12:00 AM with No comments
I was doing some tests in my lab and I wanted to have Highly available Storage. I was configured iSCSI Datastores in my VMware Network and basically adding multipathing to the Storage creates the Highly available solution in my iSCSI Storage Network. 

There is a good point in this iSCSI Multipathing, iSCSI allow only one path per initiator and that's where you need to consider this configuration and use this multipath mechanism for iSCSI Networks.

Here I'm not going to show you how to add a iSCSI Datastore to a VMware host and I'm focusing to show you the multipathing configuration. Ideally, you need to use the VMware Standard switch for this Configuration as you need to maintain separate redundancy for the Datastores. 

As I mentioned earlier, iSCSI only allow one path per initiator and if you try to add another 'vmkernel" to the storage when you already have one, it doesn't show you the "vmkernel" under port binding of your "software initiator". 


There are two ways that we can do this mutipathing redundancy configuration.

  • Create two vSwitches (Standard) and two port groups with a vmnic each
  • Create one vSwitch (Standard) and crate two port groups
I'm going to show these two methods in this article:

Create two vSwitches and two portgroups with vmnics 

This is the setup of the VMware network configuration

This is kind of a easy pretty straight forward connection. Now go to your "Software iSCSI" adapter and click on "Properties"


Once you get the iSCSI initiator Properties go to "Network Configuration" tab and click on "Add..."


Since there is only one path for each port groups it shows the available "vmknics" here.


Add these two "vmknics" and close the iSCSI initiator window. Check the path status "not use" these paths are not yet activated.


Check the path status again and you will be able to identify the "Active" status of one of the paths.


That's only from this configuration as I mentioned before this is a pretty straight forward and easy configuration.

Create single vSwitch with two port Groups and two vmnics

This is the second method and I'm going to crate single vSwitch with two port groups and two vmnics. If it support only one path for iSCSI how we can use this method with two vmnics? that's where we need to point one vmnic at a time. 

This is the vSwitch setup for this configuration 

Once you created two port groups and assigned vmnics to the switch, click on "Properties..." of the vSwitch and open the vSwitch Properties. Select one of the Port group and click on "Edit..."


Once you get the port group properties window select the "Override switch failover oreder:" check box



And  move down one of the "vmnic" to the "Unused Adapters" category, you need to keep in mind which vmnic moved down in this step as we need to move down the other vmnic in the next step. In my case it is "vmnic3"


Click on "OK" and do the same configuration to the other Port group and move the other vmnic. In my case it is "vmnic2" and click "OK" and submit the change. 


Now you can add the Port groups to your "Software iSCSI" adapter port binding as I explained above and check the "Path Status" 


That's it and you have successfully configured the multipathing and high availability in your iSCSI Storage Network.
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