Ok, the problem is now solved. To me it seems that SnapDrive can't really do NPIV without manually creating the correct igroups before. When I installed SnapDrive it only created 2 igroups with the ESX WWPN on the filer. I would have expected it to create the igroups with the WWPN of the V-PORT that was generated when activating NPIV for the VM. This was not the case. Since the LUN's where now mapped to only the WWPNs of one of the ESX hosts in the cluster, it could not be taken over by the other ESX. I have now manually created the igroup with all the WWPN's of the ESX and the generated V-PORT WWPNs of the VM. I mapped the igroup to the luns and powered on my virtual machine again.
From the filer console I can now see that the V-PORT initiators are logged in:
GEDACV2_NPIV (FCP):
OS Type: vmware
Member: 21:01:00:1b:32:ba:90:29 (logged in on: vtic, 0d)
Member: 21:00:00:1b:32:9a:90:29 (logged in on: vtic, 0c)
Member: 21:01:00:1b:32:ba:42:de (logged in on: vtic, 0d)
Member: 21:00:00:1b:32:9a:42:de (logged in on: 0c, vtic)
Member: 28:37:00:0c:29:00:00:19 (not logged in)
Member: 28:37:00:0c:29:00:00:18 (not logged in)
Member: 28:37:00:0c:29:00:00:17 (logged in on: vtic, 0c)
Member: 28:37:00:0c:29:00:00:16 (logged in on: vtic, 0d)
Member: 28:37:00:0c:29:00:00:15 (not logged in)
ALUA: Yes
I'm not sure if the OS type is correct but SnapDrive used the same type when automatically creating the initiators.
Now both ESX servers can see the LUNs.
Regards,
Oliver