iSCSI Software Adapter Offline

[MikeF007]

I am using vSphere 6.0.0 Update 2 in a lab environment. After enabling the iSCSI Software Adapter, it's status is offline. This shows up when selecting the ESX host and choosing Manage | Storage | Storage Adapters | iSCSI Software Adapter. I have tried disabling the adapter, rebooting, re-enabling, and rebooting to no avail. My network is working in that I can ping both directions between the ESXi host and the Server 2012R2 iSCSI File and Storage iscsi service. I have a successful target set up. I can use "nc -z ip_address 3260" from the ESX host to the target successfully. The storage adapter properties list a proper iscsi iqn name. The iscsi server (Server 2012R2 iSCSI File and Storage Services) lists the ESX host and shows online. The lun target shows up on the server as not connected. I've had my iscsi software adapter online and the connection to storage working with the same versions of each product (ESX host, vCenter, vsphere, and Server 2012R2 file services), so I don't believe the answer is to upgrade any of the products. I have simply rebuilt the lab environment from the ground up but now it doesn't work. The iscsi target sees the ESX host, but there is no path. I believe everything would fall into place if I could resolve why the iscsi adapter is offline - all the other setup involved is in place and looks correct. All of my ports are showing as Link Up. Any suggestions would be greatly appreciated!

[MikeF007]

I solved my issue by reinstalling ESXi. However, I would be interested in knowing why the iSCSI software adapter would not go online. I am using the exact same configuration and software versions as before the reinstallation, but after reinstalling, the adapter came online as it should. Any thoughts?

[DJSevene]

Mike,

I've seen this once in ESXi 6.5, if you run into it again, you can unbind and bind the VMK ports and it will come back.  I'm unsure of why it happens.  I've gotten vm-supports and looked for the cause and I was unable to find anything.  To my knowledge, the following do not work:

- Enable/Disable iSCSI software adapter

- Rebooting host

I thought this was limited to ESXi 6.5, it's concerning that it shows up in ESXi 6.0 as well.

[alexkozlov]

I saw it on three servers at the same time.

6.7.0 Update 2 (Build 13006603)

[DJSevene]

All,

I think I found an answer to the cause of the software iSCSI adapter going offline.  This happened to me again moving a VMware 6.7u2 Cluster from one rack to another after a proper shutdown.  Important factors related to it...

I was using the vCenter Virtual Appliance, I was using only distributed virtual switches (one for management and vMotion, one for iSCSI).  All iSCSI storage was behind the software adapter.    The new environment had different cabling and different physical NIC connections.  I believe that a ESXi host comes up with no original physical path.  Some proactive code may disable the software adapter as a protective measure. 

It's my understanding that the dVS is functionally similar to a read-only standard switch (managed at the vCenter level, with an updated RO copy sent to the switches on changes).  With no physical way to get an updated copy of the dVS, there might be code logic to disable the software adapter.  With two read only distributed switches, I had to add a standard switch with one of the new physical connection to the vCenter.  I reconfigured the dVS to be physically correct, and then unbound and bound the connections.  The environment immediately came back.

Hope this helps folks.  I understand the logic, but I might look into submitting a request for a CLI option that lets you set the iSCSI software adapter back online without the need of bind/unbind.

Best of Luck,

David