Configuring Software iSCSI Port Binding on ESXi 5

by admin

By default, the default iSCSI configuration creates only one path to each iSCSI target. Port binding is used to provide multiple paths to an iSCSI array. With vSphere 5, iSCSI port binding can be configured in the vSphere client as well as the CLI. Prior to ESXi 5, port binding could only be configured using the CLI. There are a few things to bear in mind before configuring port binding:

• The array’s target ports must reside in the same layer 2 segment/IP subnet  as the vmkernel interfaces that will connect to it.
• All VMkernel ports used for iSCSI must reside in the same layer 2 segment / IP subnet.
• All VMkernel ports used for iSCSI must be on the same vSwitch.
• Network routing is not supported. Enabling multipathing removes the ability to route to the iSCSI target.

iSCSI Network Configuration

The first step to configuring software iSCSI is to set up the appropriate network configuration:

1. In the Configuration | Networking screen in the vSphere client, click Add Networking
2. Select VMkernel and click Next
3. Select Create a vSphere Standard Switch
4. Select the adapters you wish to use for iSCSi traffic and click next. You will need at least two adapters.
5. Label the Portgroup appropriately. Click Next.
6. Configure an IP address for the VMkernel portgroup. This needs to be in the same IP subnet as the iSCSI targets, as discussed above. Click Next.
7. Review the summary screen, then click Finish to create the new vSwitch.

The next step is to go into the settings of the new vSwitch and create additional portgroups for each nic you have assigned to the vSwitch. In my lab I used two nics so created two portgroups. My resulting configuration looked like this: