Created attachment 761860 [details]
logs

Description of problem:

I extended a domain from a lun which disappeared after the login and extend fails with the following unclear error: 

Error while executing action Edit SAN Storage Domain configuration: Physical device initialization failed. Check that the device is empty. Please remove all files and partitions from the device.

Version-Release number of selected component (if applicable):

sf18

How reproducible:

100%

Steps to Reproduce:
1. in iscsi storage type with two hosts, create a domain from a lun on one server
2. in storage tab -> select the domain -> edit -> discover luns on a second storage server and log in to one lun
3. block connectivity to the lun from storage server2 and press OK on the edit domain dialogue

Actual results:

extend fails with the following error: 

Error while executing action Edit SAN Storage Domain configuration: Physical device initialization failed. Check that the device is empty. Please remove all files and partitions from the device.

Expected results:

we need a clearer message for user. 
also this part is not relevant: 

Check that the device is empty. Please remove all files and partitions from the device.

Additional info: logs