When you try to mount a backup job with Veeam Backup & Recovery you will be promoted with an error Failed on Checking if vPower NFS datastore is mounted on host.
On vSphere Client, you will get a failed task on Create NAS Datastore “An error occurred during host configuration” the error in the view details is “Operation failed, diagnostics report: Unable to resolve hostname” of veeam server.
Error after second attempt:
Since my vSphere Infrastructure sets on different subnet other that my domain and where the Veeam Machine sets, I have to edit the etc host of the ESX hosts as well as the Veeam Machine.
Ping by name and IP successful and vPower NFS successfully mounted the backup image to the ESX host and started working fine.
Note: I used Veeam 5 with ESX 4.1 and I didn’t face this kind of issue. Since I have upgraded to Veeam 6 and ESXi5 U1, I started facing this issue.