Configuring site information for the system

To configure a HyperSwap^® system topology, you must assign enclosures, external storage systems, and hosts to a specific site.

Using the management GUI

You can use the Modify System Topology wizard in the management GUI to easily configure the site names and assign all necessary objects on your system to a site. Complete the following steps to access the Modify System Topology wizard.

In the management GUI, select Monitoring > System. In the Actions menu, select Modify System Topology.
Follow the wizard to complete the configuration of the HyperSwap topology.

Using the CLI

You can also use the command-line interface to configure site information and configure the system as a HyperSwap topology. Separate commands are used for each configuring site definitions for the necessary objects on the system. Although you do not need to name sites, creating names that are based on the location or use of the site simplifies management of the HyperSwap topology. Complete the following steps to configure site information and set the system as a HyperSwap topology:

For easier management of the HyperSwap topology, create specific names for each site on the system. If names are not specified, sites can be referred to by their default name or numeric ID. Enter the following command to create specific names for each site.
```
chsite -name losangeles 1
```
In this example, site 1 is now named losangeles. To rename the other sites in the HyperSwap topology, issue the same command with names for the other sites:
```
chsite -name sandiego 2
chsite -name quorum 3
```
In this example, site 2 is now named sandiego and site 3 is named quorum.
Note: IP quorum applications can be used at a third site to provide a tie-break if there is a loss of connectivity between site 1 and site 2. For more information, see the IP quorum configuration information.
Enter the following commands to assign existing node canisters in each control enclosure (I/O group) to sites:
```
chnodecanister -site losangeles canister1
```
```
chnodecanister -site losangeles canister2
```
Both node canisters in a control enclosure must be assigned to the same site. In this example, the I/O group that contains canister1 and canister2 are assigned to the site losangeles. To assign the node canisters in another I/O group to the other site, enter the following commands:
```
chnodecanister -site sandiego canister3
```
```
chnodecanister -site sandiego canister4
```
In this example, the I/O group that contains canister3 and canister4 are assigned to the site sandiego. You must assign a site for all node canisters in the system.
Enter the following command to assign existing external storage systems to sites:
```
chcontroller –site losangeles storagesystem1
```
In this example, storagesystem1 is assigned to site losangeles. To assign a storage system to the other site, enter the following command:
```
chcontroller –site sandiego storagesystem2
```
In this example, storagesystem2 is assigned to site sandiego.
If you plan to use an external storage system to provide quorum, then you must assign that to the third site. Alternatively, an IP quorum application can be used to provide quorum. For more information, see the IP quorum configuration information. To assign an external storage system to the third site, enter the following command:
```
chcontroller –site quorum storagesystem3
```
In this example, storagesystem3 is assigned to site quorum.
You must assign a site for all storage systems that are present in the configuration.
Enter the following command to assign existing hosts to sites:
```
chhost -site losangeles host1
```
In this example, host1 is assigned to site losangeles. If you have other hosts, you can assign them to other sites:
```
chhost -site sandiego host2
```
In this example, host2 is assigned to site sandiego.
After all the site assignments are complete for enclosures, storage systems, and hosts, set the system topology to hyperSwap by entering the following command:
```
chsystem -topology hyperswap
```
Optionally, configure bandwidth settings for the background copy operations between each site by entering the following command:
```
chpartnership -linkbandwidthmbits 2048 -backgroundcopyrate 50 mysystem
```
Background copy is the term that is used for the initial synchronization and any subsequent resynchronization traffic for HyperSwap volumes in the system.

After you complete these steps, you can configure HyperSwap volumes to create copies at each site.