SnapDrive for Windows and cluster iGroups

[#1]

Hi All,

Can someone please point me to right direction why I can't see igroups in Snapdrive for Windows (SDW) which have WWN of all nodes of a cluster.

Currently I am using SDW 6.3 and Ontap 7.3.2 and if I create an igroup which has WWN of a single node only then I can see in SDW however when I have an igroup having all nodes of cluster then SDW doesn't list it at all.

Do we know why this limitation is in effect as looking at 256 igroups limit across filer cluster we are little worried that we may hit the wall very soon.

Cheers,

Lovik

[#2]

Lovik,

Do you have either the MS or NetApp MPIO software loaded on this host? Does the program show the multiple paths (or nothing)?

As a side note: are you creating everything through SDW (lun, igroup) or through System Manager, FilerView or CLI?

Peace,

Shane

[#3]

Hi Shane,

We are using NetApp MPIO and everything is correct, looks like I wasn't clear enough on my question.

Actually when I create a LUN from SDW and use automatic mapping than SDW creates 4 igroups on filer for 2 node windows cluster (2 FC port/host), however going this way soon we will hit max igroup limit of filer which we don't want.

Now if we manually create an igroup on filer which has all 4 WWN then we can't create luns from SDW as on mapping screen SDW doesn't lists igroup which we have created manually because it has WWN of other windows cluster node as well, however if we create one igroup per host which has both the ports of host then it lists correctly in igroup window.

So my question is why SDW can't list an igroup which has WWN of other node of cluster?

Hope my lengthy question makes sense.

[#4]

Hi Mohit,

Can you confirm the following is ok?

Guidelines for mapping LUNs to igroups
There are several important guidelines you must follow when mapping LUNs to an igroup.
• You can map two different LUNs with the same LUN ID to two different igroups without having
a conflict, provided that the igroups do not share any initiators or only one of the LUNs is online
at a given time.
• Make sure the LUNs are online before mapping them to an igroup. Do not map LUNs that are in
the offline state.
• You can map a LUN only once to an igroup or a specific initiator.
• You can add a single initiator to multiple igroups. but the initiator can be mapped to a LUN only
once. You cannot map a LUN to multiple igroups that contain the same initiator.
• You cannot use the same LUN ID for two LUNs mapped to the same igroup.
• You cannot map a LUN to both FC and iSCSI igroups if ALUA is enabled on one of the igroups.
Run the lun config_check command to determine if any such conflicts exist.

http://now.netapp.com/NOW/knowledge/docs/ontap/rel733/pdfs/ontap/bsag.pdf

Page 53

[#5]

The key point is when an igroup has wwn of only one node then every thing works as expected however as soon as I introduce another node of cluster SDW doesn't list it at all.

So I believe all the points you mentioned doesn't apply here.

[#6]

Create one igroup per node and use SDW with the manual igroup selection option.

Example :

Create igroup1 with wwns of Node1

Create igroup2 with wwns of Node2

Choose the manual option in SDW during igroup selection.

Igroups 1 & 2 should show.

Thanks,

~Satish

[#7]

Thanks Satish!

[#8]

I think I should have said " as soon as I introduce another node of cluster in same igroup SDW doesn't list it at all."

so what you said is correct and works fine but I want is single igroup for both the nodes.

Create igroup1 with wwns of Node1 ----- Shows in SDW correctly

Add wwn of Node2 in igroup1  ----- igroup1 doesn't shows in SDW

[#9]

Hi,

I know this is an old thread but I'm having an issue with multiple initiators contained within the same igroup and SnapDrive. Turns out SnapDrive doesn't support this:

https://kb.netapp.com/support/index?page=content&id=3012721

It does say this in the SD 6.3 manual but relating to FC RDMs, which I missed because I am doing standard LUN presentation through to a physical host - bit annoying!

Hope this helps.