This is a page intended to give a small summary on creating usable storage on a NetApp SAN. Topics covered are:

• Terminology
• Create a volume
• Create a LUN
• Create an initiator group
• Create a mapping between an initiator group and a LUN
• References

Aggregates are containers that capture all the physical aspects of storage such as disks and RAID groups. An aggregate can contain one or more flexible volumes or a single traditional volume. You cannot mix volume types on an aggregate.
Consider this caveat when you're creating aggregates.

There are two types of volumes on a NetApp:

• Traditional volumes

Traditional volumes combine the physical layer of storage (the disk and RAID properties) with the logical layer of the file system (the volumes and any other containers that are used to store files and directories).

• Flexible volumes (also called FlexVol volumes)

Flexible volumes allow you to manage the logical layer of the file system independently of the physical layer of storage. Multiple flexible volumes can exist within a single separate, physically defined aggregate structure of disks and RAID groups. Flexible volumes contained by the same aggregate share the physical storage resources, RAID configuration, and plex structure of that aggregate.

Note that in this article we'll work with flexible volumes only.

The Logical Unit (LUN) is a unit of storage on a storage system that is accessed by clients.

An initiator group (igroup) specifies which initiators can have access to a LUN. When you map a LUN on a storage system to the initiator group, you grant all the initiators in that group access to that LUN. If a host is not a member of an igroup that is mapped to a LUN, that host does not have access to the LUN.

In the case of iSCSI clients, hosts are identified in an initiator group by their node names. In the case of FCP clients, hosts are identified in an initiator group by their World Wide Port Names (WWPNs).

A Snapshot copy is a read-only image of the entire Data ONTAP file system. It reflects the state of the file system at the time the Snapshot copy is created.

Go into the filer, click on aggregates, click manage and you can see how many free space there is on each aggregate:

Go into the filer, click on volumes and click add. A new window pops up, displaying a wizard for making a new volume. Follow the directions but keep the following configurations in mind:
Choose to create a flexible volume.
Give an appropriate name, select POSIX as language and enable UTF-8.
Select the correct aggregate and keep the space guarantee on volume.
These setting should be according to your needs and environment. I don't use snapshots, which makes me select these settings.

After creating the volume you'll need to modify some of the settings. To modify a volume go into the filer, click on volumes and click manage. Then click the volume you want to modify. This will get you into the properties of the volume. Then click modify, which will get you another wizard to modify the volume. Follow the directions and modify what you want to modify:

• Enable Convert To Unicode because this will save conversion time and facilitate file sharing.

• Enable Minimal Read Ahead if the accessing clients will be ESX clients. In almost any other case leave this disabled.
• Disable Update Access Time because this will prevent a lot of minor writes in the filesystem.

Because I don't wanna use snapshots I also modify the snapshots settings. To do so, go into the filer, click on volumes, click on snapshots and select the correct volume. Then disable Scheduled Snapshots:

Go into the filer, click on LUNs and click add:

• Give a nice name, something descriptive would be nice.
• Also give the correct LUN protocol type. It's very important to select the correct type. For me, in this case it's VMware, other possibilities include AIX, linux and NetWare.
• If you give a wrong size you'll receive this error:

• If you click manage when you're done you'll see the new created LUN in the list:

Go into the filer, click on LUNs, click on Initiator Groups and click on add.
This is with Fibre Channel.
This is with iSCSI.

If you go back to managing LUNs, to the originally created lun you can create a mapping between an initiator group and a LUN id:
Click the “No Maps” button on the right, and click the “Add Groups to Map” button in the right top corner:
Select the just created group.
Determine the correct LUN id. You can make up the LUN id, there's just one restriction. For the clients connecting to the storage it has to be an unique LUN id. Which means, if the clients already have a few luns you should make a LUN id not in use yet.

You've created a new LUN, now it's time to put it in use: Click here if you've created an iSCSI initiator group
Click here if you want to configure ESX to make use of the Fibre Channel LUN

NetApp homepage
Wikipedia on UTF-8
Wikipedia on POSIX