Target portal groups enable you to efficiently manage iSCSI sessions between initiators and targets. Although Data ONTAP manages target portal groups using network interfaces by default, you can also manage these groups using IP addresses, starting with Data ONTAP 7.3.3. This is required if you want to perform an online migration of vFiler units, which allows you to nondisruptively migrate data from one storage system to another.
When you migrate data, the target portal group tag on the destination network interface must be identical to the target portal group tag on the source network interface. This is problematic in a MultiStore environment because the source and destination storage systems might be of different hardware platforms. Changing the target portal group tags after migration is not sufficient because some hosts, such as HP-UX and Solaris, do not support dynamic iSCSI target discovery, which results in a disruption of service to those hosts in the change process.
If offline (disruptive) migrations are not problematic in your environment, or if all of your hosts support dynamic iSCSI target discovery, then IP-based target portal group management is unnecessary.
If you choose to implement IP-based target portal groups by enabling the iscsi.ip_based_tpgroup option, interface-based target portal groups are automatically converted to IP-based target portal groups, and any future target portal group assignments are IP-based as well. However, note that if you are migrating between a system with IP-based target portal groups and a system with interface-based target portal groups, the target portal group information is lost and the iSCSI service might be disrupted.
For more information on target portal groups, see the Data ONTAP SAN Administration Guide for 7-Mode.
For more information about the NetApp Management Console provisioning capability, see the Provisioning Manager and Protection Manager Guide to Common Workflows for Administrators.