Serving Data in Cluster-Mode

NetApp Data ONTAP 8.1 operating in cluster-mode offers attractive capabilities such as scale-out, non-stop operations, multi-tenancy, and much much more. 


That’s fantastic! However, if you are handed an n-node (let’s say, 2-node) cluster running Data ONTAP 8.1 operating in cluster-mode, how do you serve data to a Windows host?


Well, the key entity in such a cluster is called Vserver, which is a logical entity. A cluster can have many Vservers. Each Vserver is associated with some physical resources such as physical disks and network ports within the cluster. To an end user or a host machine, a Vserver is like a virtual storage controller. The host does not have direct access to the physical resources inside the cluster. But the host can read and write data from and to one or more Vservers.


ONTAP 8.1 provides a Vserver setup wizard and its helpers (called subwizards, performing Network, Storage setup, etc.) Granted, you can rely on wizardry to setup the Vserver and serve data to the host. But I’ll take a different path. I’ll use simple command line interface (CLI); and it only needs 7 steps. My hope is that by demonstrating to you how to setup a Vserver to serve data to a Windows host using CLI, you can see what the wizards do behind the scene and obtain a better understanding of the wizards, if you choose to use them later on. Below are the 7 steps.


A.   Create Vserver

Fig. 1 shows the command you use to create a Vserver named MyVserver on aggregate aggr1. If you don’t already have aggr1, just create it first using the aggr create… command.

Figure 1: Creating a Vserver


B.   Create FC Service

After a Vserver is created, we need to equip it with other logical entities. Recall that all NetApp FAS storage controllers can handle multi-protocols natively, such as FC, iSCSI and FCoE. So can a Vserver. Here, we’ll just use FC protocol in our example. Fig. 2 shows how to create FC service for MyVserver. Note, the command is case insensitive. To verify, use the fcp show command.

Figure 2: Creating FC service


The Target Name in Fig.2 is equivalent to the node name of a physical controller.


C.   Create Logical Interface (LIF)

To a Vserver, an FC Logical Interface, or LIF, is just as an FC port to a physical controller. The commands shown in Fig. 3 can be used to create a LIF and verify that the LIF is indeed created.

        Figure 3: Creating a LIF


The Network Address/Mask in Fig. 3 is equivalent to an FC port’s WWPN on a physical controller.  The FC LIF’s Network Address and the Vserver’s Target Name are then used by Zone Admin in FC switch to establish the FC link from host to switch and then from the switch to the cluster and Vserver.


D.   Create iGroup

To create an iGroup, we need to know the WWPN of the HBA inside the host, or initiator’s WWPN. Fig. 4 shows how to obtain this information.

Figure 4: Getting FC initiator WWPN


Then, the command igroup create… is issued, as in Fig. 5, to create the igroup called MyIGroup.

Figure 5: Creating an iGroup


E.   Create Volume

Fig. 6 shows how to create a FlexVol volume.

Figure 6: Creating an volume




F.   Create LUN

Once we have a volume, it is not difficult to create a LUN (see Fig. 7).

Figure 7: Creating a LUN


G.   Map LUN to Host

Finally, we need to map the LUN to the iGroup MyIGroup. Fig. 8 shows how to do that.

Figure 8: Mapping the LUN to the host


That’s all from the storage side.


Now, switch to the Windows host. Using the Disk Management tool, we see that Disk 17 (of size 19GB) is the LUN we just mapped to the host (see Fig. 8). After initialize and format this disk, we can use it to serve data.

Figure 9: Mapping the LUN to the host


To recap, these are the 7 steps to configure the storage in cluster-mode in order to server data to a Windows host.  Some of the steps are familiar as in 7-mode. The new concepts are Vserver and LIF. If you know how to administer a controller in 7-mode, then you are more than half way there.


Thanks for reading.

on ‎2013-01-18 05:02 AM

I am starting to learn the c-mode now, and its really a good writeup. I see that apart from vserver and lif concepts, there is a significant change in the CLI. NetApp has been pushing c-mode hard but I am not sure how will it take for existing customers to take this plunge. I see that 7-mode still rules in the majority of the installations. I am hoping c-mode is the way forward. Thanks again.

I just noticed, for FCP , for creating a lif, you used 'create' command to create lif, but you placed '-lif' after -vserver switch, whereas in your iSCSi LIF example (separate blog) you used 'create -lif' , so does it matter ?



lwei Former NetApp Employee on ‎2013-01-18 07:11 AM

Great observation Ash! In this case, the order doesn't matter, since the meaning of each switch is unambiguous.

BTW, Clustered ONTAP is the future. Transitioning to Clustered ONTAP will happen. So, it's great you get yourself familiar with it before taking the plunge :-)