A portset consists of a group of FCP target ports. You bind a portset to an igroup, to make the LUN available only on a subset of the storage system's target ports. Any host in the igroup can access the LUNs only by connecting to the target ports in the portset.
If an igroup is not bound to a portset, the LUNs mapped to the igroup are available on all of the storage system's FCP target ports. By using portsets, you can selectively control which initiators can access LUNs and the ports on which they access LUNs.
You use portsets for LUNs that are accessed by FCP hosts only. You cannot use portsets for LUNs accessed by iSCSI hosts.
Portsets are supported only with the single_image cfmode setting. They are not supported with other cfmode settings. The single_image setting makes all ports on both systems in the cluster visible to the hosts. You use portsets to fine-tune which ports are available to specific hosts and limit the amount of paths to the LUNs to comply with the limitations of your multipathing software.
The single_image mode is not the default cfmode setting for a new system or for an upgrade. Before you use portsets, you must change your cfmode setting to single_image.
Note
Make sure your portset definitions and igroup bindings align with the cabling and zoning requirements of your configuration.
For detailed information about single_image mode, see How Data ONTAP supports FCP with clustered systems.
For procedures that describe how to change your cluster's cfmode setting to single_image mode, see the following documents:
When you upgrade to Data ONTAP 7.1, all ports are visible to all initiators in the igroups until you create portsets and bind them to the igroups.
Portsets enable you to control queue resources on a per-port basis. If you assign a a throttle reserve of 40 percent to an igroup that is not bound to a portset, then the initiators in the igroup are guaranteed 40 percent of the queue resources on every target port. If you bind the same igroup to a portset, then the initiators in the igroup have 40 percent of the queue resources only on the target ports in the portset. This means that you can free up resources on other target ports for other igroups and initiators.
Before you bind new portsets to an igroup, verify the igroup's throttle reserve setting by using the igroup show -t command. It is important to check existing throttle reserves because you cannot assign more than 99 percent of a target port's queue resources to an igroup. When you bind more than one igroup to a portset, the combined throttle reserve settings might exceed 100 percent.
igroup_1 is bound to portset_1, which includes ports 4a and 4b on each system in the cluster (FilerA:4a, FilerA:4b, FilerB:4a, FilerB:4b). The throttle setting of igroup is 40 percent.
You create a new igroup (igroup_2), with a throttle setting of 70 percent. You bind igroup_2 to portset_2, which includes ports 4b on each system in the cluster (FilerA:4b, FilerB:4b). The throttle setting of the igroup is 70 percent. In this case, ports 4b on each system are overcommitted. Data ONTAP prevents you from binding the portset and displays a warning message prompting you to change the igroup throttle settings.
It is also important to check throttle reserves before you unbind a portset from an igroup. In this case, you make the ports visible to all igroups that are mapped to LUNs. The throttle reserve settings of multiple igroups might exceed the available resources on a port.
For details about igroup throttles, see Managing Fibre Channel initiator requests.
For clustered systems, it is recommended that when you add local ports to a portset, that you also add the partner system's corresponding target ports to the same portset. For example, if you have local systems's target port 4a port in the portset, then make sure to include the partner system's port 4a in the portset as well. This ensures that cluster takeover and giveback occurs without connectivity problems.
To create a portset, complete the following step.
If you do not bind an igroup to a portset, and you map a LUN to the igroup, then the initiators in the igroup can access the LUN on any port on the storage system. To bind an igroup to a portset, complete the following step.
| 1 |
igroup bind igroup_name portset_name |
To add a port to a portset, complete the following step.
| 1 |
portset add portset_name port... portset_name is the name of the portset. port is the target FCP port. You can specify more than one port. You specify a port by using the following formats: |
To remove a port from a portset, complete the following step.
| 1 |
portset remove portset_name port... portset_name is the name of the portset. port is the target FCP port. You can specify more than one port. You specify a port by using the following formats: |
If you unbind or unmap an igroup from a portset, then all hosts in the igroup can access LUNs on all target ports. To unbind an igroup from a portset, complete the following step.
| 1 |
igroup unbind igroup_name |
To view the ports in a portset, complete the following step.
| 1 |
portset show [portset_name] If you do not supply portset_name, all portsets and their respective ports are listed. If you supply portset_name, only the ports in the portset are listed. |
To show which igroups are bound to portsets, complete the following step.
| 1 |
igroup show igroup_name |
Before you destroy a portset, make sure you unbind it from any igroups. To destroy a portset, complete the following step.
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Part No. 210-01094_B0
File: c7aclus9.htm
Last updated: 08-Dec-2005 13:25:31