The Hidden Device at LUN0

You might experience a hidden device at LUN0 if both of the following conditions occur:

The vhba binary can run at least vHBA Protocol Version 1.2, but is currently running Version 1.0
You replaced the device at LUN0 with another device.
Note:
A hidden device occurs only at LUN0 because a device at LUN0 is a special case for the vHBA subsystem, see Simulating a LUN0. If you insert another device at a non-LUN0 path, the new device is unusable because the WWN of the new device does not match the WWN of the original device. vhba issues the following message:
```
WARNING: {vh@0,w200000110d211500,3} WWNs of (old, new) do not match: (naa.600110d000211500010900008207288b, naa.600110d000211500010900009deb2582)
```
For a LUN0 device, the most basic SCSI commands must remain operational. vhba fails gracefully for all other SCSI commands to ensure that an unauthenticated device is not modified.

If vhba detects these conditions, the new device is hidden by the original device. vhba issues the following message:

WARNING: {vh@0,w200000110d211500,0} new(naa.600110d0002115000109000025d42777 is hidden by old(naa.600110d0002115000109000025d4274a)

When you restore the original device to the LUN0 path, vhba no longer filters any I/O that is sent to that path and device. vhba issues the following message:

WARNING: {vh@0,w200000110d211500,0}: was restored to expected wwn(naa.600110d0002115000109000025d4274a)