vSphere5 and Broadcom iSCSI Adapter IQN name contains localhost

Just a quick post about something I noticed while configuring a new vSphere5 host with a Broadcom iSCSI Adapter. This  is not a real iSCSI HBA but a vmnic with TCP/IP offloading. This offloading feature benefits the performance of iSCSI because the vmkernel doesn’t have to do as must work as with a normal vmnic without the offloading feature.

The Broadcom vmnic will show up as a vmhba in the configuration screen of your vSphere5 host.

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With the Software iSCSI client provided by VMware the IQN name of this adapter is created when you enable the adapter. This IQN name has a naming convention like: iqn.1998-01.com.vmware:hostname:string where hostname is the name of your vSphere host and string is a random value. Now with the Broadcom card the hostname is where the pain is. As the Broadcom card is enabled by default the hostname is detected as localhost (as seen in the screenshot).
Of course this is not what we want. As when we have a 32 vSphere host all showing up in your iSCSI storage as localhost, it’s now easy to see anymore witch iqn belongs to a vSphere host. Of course the string behind the hostname will be unique and you can document the iqn, but it’s easier and thus better manageable if the iqn contains the real hostname of the server who you have configured during installation.

As of now, the only way I figured out to change the hostname in the iqn name of your vmhba is to go to the properties of you vmhba, on the General tab click configure and change the iqn name in the iSCSI Name field.

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After doing so you have to to a rescan of the vmhba in order to update the information in your iSCSI target. If you have used the previous iqn name containing the hostname as localhost you have the setup your lun masking in your iSCSI target again.

Note: I have tested this behavior with Broadcom NICs, I don’t know if the behavior is similar on other NICs who have offloading features.