You create LUNs and igroups using one of the following methods:
This method prompts you through the process of creating a LUN, creating an igroup, and mapping the LUN to the igroup. For information about this method, see Creating LUNs with the lun setup program.
This method provides a LUN Wizard that steps you through the process of creating and mapping new LUNs. For information about this method, see Creating LUNs and igroups with FilerView.
This method allows you to create one or more LUNs and igroups in any order. For information about this method, see Creating LUNs and igroups using individual commands.
SnapDrive furnishes a Windows-like interface to manage LUNs on a filer. This product provides online storage configuration, LUN expansion, and streamlined storage management. Integrated with NetApp SnapshotTM functionality, SnapDrive creates point-in-time images of data stored in LUNs that are connected to the filer, for backup, archiving, recovery, and asynchronous mirroring. For more information, see the SnapDrive Installation and Administration Guide.
Note
If you choose to use SnapDrive, all LUN management functions must be performed using the SnapDrive interface.
Whichever method you choose, you create a LUN by specifying the following attributes:
The path name must be at the root level of a qtree or a volume that specifies where the LUN is located. Do not create LUNs at /vol/vol0.
For clustered filer configurations, NetApp recommends that you distribute LUNs across the filer cluster.
Note
You might find it useful to provide a meaningful path name for the LUN. For example, you might choose a name that describes how the LUN is used, such as the name of the application the kind of data that it is, or the user using the data. Examples are /vol/database/lun0, /vol/finance/lun1, or /vol/bill/lun2.
The host operating system type (ostype) indicates the type of operating system running on the host that accesses the LUN, which also determines the geometry used to access data on the LUN.
Not all versions of Data ONTAP support all operating system types. Neither protocol (FCP and iSCSI) supports all operating systems. For information about what is supported, see the FCP/iSCSI Configuration Guide or the release notes that came with your version of Data ONTAP.
When you create a LUN, you specify its size as raw disk space, depending on the filer and the host. You specify the size, in bytes (default), or by using the following multiplier suffixes.
The usable space in the LUN is dependent on host or application overhead requirements. For example, partition tables and host file system metadata reduce usable space for applications. In general, when you format and partition LUNs as a disk on a host, the size of the disk is smaller due to the overhead required by the host.
The disk geometry used by the operating system determines the minimum and maximum values of LUNs. Windows geometry is characterized by 63 sectors/track and 255 heads. Solaris geometry is characterized by16 heads and a cylinder size which is a multiple of 1MB. The minimum LUN size is 4 cylinders. For Solaris, that dictates a minimum LUN size of 4MB. For Windows, that dictates a minimum of 31.5MB. For information about the maximum sizes for LUNs, see the SAN HBA host attach kit documentation for your host.
You use this attribute to store alphanumeric information about the LUN. You can edit this description at the command line or with FilerView.
A LUN must have a unique LUN LUN ID so the host can identify and access the LUN. This is used to create the map between the LUN and the host.
When you create a LUN, the space reservation is turned on. NetApp recommends that you keep this setting on.
Initiator groups are tables of WWPNs of hosts that you use to control access to LUNs. Typically, you want one host to have access to a LUN. However, if you are using multipathing software, or have clustered hosts, you need to have redundant paths to the same LUN.
You can create igroups that specify which initiators have access to the LUNs either before or after you create LUNs, but you must create igroups before you can map a LUN to an igroup.
Initiator groups can have multiple initiators, and multiple igroups can have the same initiator. The following table illustrates how four igroups give access to the LUNs for four different hosts using the FCP service. The clustered hosts (Host3 and Host4) use the same igroup for common access to the LUNs mapped to solaris-group2. The igroup named solaris-group3 contains the WWPNs of Host4 to store local information not intended to be seen by its partner.
Whichever method you choose, you create an igroup by specifying the following attributes:
This is a case-sensitive name that meets the following requirements:
The name you assign to an igroup is independent of the name of the host that is used by the host operating system, host files, or DNS. If you name an igroup sun1, for example, it is not mapped to the actual IP host name (DNS name) of the host.
Note
You might find it useful to provide meaningful names for igroups, ones that describe the hosts that can access the LUNs mapped to them.
The type is -f for FCP if it contains WWPNs or -i for iSCSI if it contains iSCSI node names. An igroup can contain only one type of unique identifier of nodes, either FCP or iSCSI.
The ostype indicates the type of operating system used by all of the initiators in the igroup. All initiators in an igroup must be of the same ostype.
Not all versions of Data ONTAP support all ostypes. Neither protocol (FCP and iSCSI) supports all operating systems. For information about what is supported, see the FCP/iSCSI Configuration Guide or the release notes that came with your version of Data ONTAP.
You can specify the WWPNs of the initiators when you create an igroup. You can also add them or remove them at a later time.
Whichever method you choose, you map a LUN to an igroup by specifying the following attributes:
You must specify the path name of the LUN to be mapped.
You must specify the name of the igroup that contains the host you want to give LUN access to.
You assign a number for the LUN ID or accept the default LUN ID. Typically, the default LUN ID begins with 0 and increments by 1 for each additional LUN as it is created. The range of valid LUN ID numbers are host-dependent. For example,
For information about the ranges of values to use when assigning LUN IDs for your host, see the appropriate SAN Host Attach Kit Installation and Setup Guide for your host.
The host associates the LUN ID with the location and path name of the LUN.
When you map the LUN ID to the igroup, you grant the initiators in the igroup access to the LUN. If you do not map a LUN, the LUN is not accessible to any hosts. This effectively masks access to the LUN. Data ONTAP maintains a separate LUN map for each igroup to support a large number of hosts and to enforce access control.
Use the following guidelines when mapping LUNs:
Copyright © 1994-2003, Network Appliance, Inc. All rights
reserved.
Part No. 210-00477
File: c2cr-f5.htm
Last updated: 11/21/03 13:06:55