Snapdrive only supports physical RDM?

[oweinmann]

Hi Everyone,

We recently switched from iscsi to NPIV on our virtual (VMWare) Exchange 2003 Server. Everything works perfect so far, except that the RDM's created by Snapdrive are physical. This is a problem since it's not possible to vmotion a vm with physical RDM's. We are running 2 ESX Vsphere servers in a cluster. One is hosting the Exchange 2003 VM. I need to reboot this ESX, but I can't because it can't vmotion the Exchange vm because of the physical RDM.

Any ideas?

Regards

[radek_kubka]

Hi and welcome to the forums!

it's not possible to vmotion a vm with physical RDM's.

That's actually not the case. See e.g. this discussion on VMware forums:

http://communities.vmware.com/thread/191518

Regards,
Radek

[oweinmann]

Hi and thanks for your very very quick answer.

Ok, I checked and one of the ESX hosts can't see the 2 luns that are connected to the Exchange vm. I wonder how I can get this working, because looking at filerview, I can see that snapdrive has automatically created an initiator group for the Exchange VM:

viaRPC.21:00:00:1b:32:9a:90:29.GEDACV2	FCP	21:00:00:1b:32:9a:90:29
viaRPC.21:01:00:1b:32:ba:90:29.GEDACV2	FCP	21:01:00:1b:32:ba:90:29

I guess these are the WWN's generated by the ESX for VM (NPIV). Looking at the LUNs on Filerview shows that the 2 luns are only offered to the initiators above:

vol/exchdb/exchdb01.lun	Exchange Mailstore	104.0G	online	viaRPC.21:00:00:1b:32:9a:90:29.GEDACV2 : 1 viaRPC.21:01:00:1b:32:ba:90:29.GEDACV2 : 1
/vol/exchlog/exchlog	Exchange Transaction Log	25.0G	online	viaRPC.21:00:00:1b:32:9a:90:29.GEDACV2 : 0 viaRPC.21:01:00:1b:32:ba:90:29.GEDACV2 : 0

Do I only need to map the lun as well to the second ESX host?

Regards

[radek_kubka]

Hi,

I recommend you have a good read of this doc:

http://www.netapp.com/us/library/technical-reports/tr-3749.html

More specifically, on page 109:

NetApp recommends creating an igroup for each VMware cluster. [...]

Each initiator group includes all of the FC worldwide port names (WWPNs) or iSCSI qualified names (IQNs) of the ESX Servers in the VMware cluster.

Regards,

Radek

[oweinmann]

I checked the doc on page 109 and yes it makes sense to make an igroup for each ESX cluster.

We have an igroup for each ESX server, this is not really a problem as long as we assign the sam LUN ID to the luns. The thing I don't understand is how

can the ESX server that is currently hosting the VM see the luns while the other ESX can't?

I checked zoning and there is nothing that would keep the ESX from seeing it. Ok, so I checked the lun mappings in filer view and it is only mapped to the WWN generated by ESX for the VM. There is no initiator group added to this LUN for neither ESX host. I guess by adding both ESX servers this breaks NPIV?

[oweinmann]

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

[radek_kubka]

Hi Oliver,

Many thanks for posting this.

I have tried to do some digging around NPIV on ESX, but (to say the least) it is not thoroughly described in NetApp technical documents (or if it is, I must missed the right doc).

Regards,

Radek

[oweinmann]

Hi Radek,

yes it's really really hard to find any good documentation on how to setup NPIV. The best documents I found were from brocade or Qlogic. There is nothing in the SnapDrive documentation regarding this. Even in the TR-3740 (Netapp VMWare Best Practices) there is nothing mentioned about NPIV. I'm really disappointed about this.

I'm still not a 100% sure if it is really using NPIV now. Because in SnapDrive it still only shows the WWPN's of the ESX HBA and not the virtual N-PORT WWPN's of the VM.

Best Regards,

Oliver

[satishv]

Snapdrive does not support NPIV.

Thanks,

~Satish

[oweinmann]

Thanks for ponting this out. No one at Netapp Support was able to tell me this.

Do you have any reference for this? I mean in the documentation there is just nothing mentioned about NPIV.

Regards,

Oliver

[radek_kubka]

I can only second to that request - clear documentation re NPIV support is really needed.

I couldn't find solid info around NPIV in VMware, despite a very thorough browsing in all usual places: NOW, Field Portal, Interop Matrix & TR Library.

Actually, reading just now, there is an interesting footnote in the TR-3737 on page 30:

VSS quiescing needs to be disabled in the presence of guest-mapped iSCSI LUNs or NPIV RDM LUNs (VMware KB article #1009073)

It doesn't imply, however, that utilising NPIV is not supported at all.

Regards,

Radek

[__frostbyte_9045]

Ironically, I find it frustrating that this standard isn't used on all platforms.  We are in the process of converting our SQL cluster into using one igroup per node.  Aparently, the Microsoft team didn't check with the VMware team on making best practices consistant.  Grrr...

[radek_kubka]

Snapdrive does not support NPIV.

Does anyone know whether this is still the case?

Regards,
Radek