Creating a DR Star Trio Using LUN Groups

Prerequisites

• A local LUN group has been created.
• Available storage pools exist on both the remote HyperMetro device and secondary asynchronous remote replication device.

Context

• Create a DR Star trio on the local HyperMetro device.

The remote replication consistency group (CG) containing the local HyperMetro device is in the active state, and the other remote replication CG is in the standby state.

• The procedure for creating a DR Star trio using a LUN group is the same as that for creating a DR Star trio using a protection group, except for the navigation path.

Procedure

1. Choose Services > Block Service > LUN Groups.
2. Select the desired LUN group and choose Protect > Create DR Star.

   The Create DR Star Trio page is displayed on the right.

3. Specify a name for the PG to be created. The selected LUN group will be added to the PG.
   • The name must be unique.
   • The name contains letters, digits, underscores (_), periods (.), and hyphens (-).
   • The name can contain 1 to 31 characters.

4. Select a HyperMetro domain and asynchronous remote replication remote device.
   1. In the HyperMetro Domain drop-down list, select a HyperMetro domain.

      You can click Create next to the drop-down list to create a HyperMetro domain.

   2. In the Remote Device in Async Remote Replication drop-down list, select an asynchronous remote replication remote device.

      You can click Add next to the drop-down list to add a new remote device.

5. Configure parameters for the HyperMetro CG and asynchronous remote replication CG.
   1. Click CG Parameters.

      The CG Parameters page is displayed.

   2. Configure HyperMetro CG parameters.

      Table 3-12 describes the parameters.

      Table 3-12 HyperMetro CG parameters

      Parameter	Description
      Speed	Data synchronization speed of the HyperMetro CG. Possible values are as follows: Low: Data synchronization takes a relatively long period of time. This value is used when the service load is heavy. The speed is normally from 0 MB/s to 5 MB/s. Medium: Data synchronization takes a relatively short period of time. This value is used when the service load is relatively heavy. The speed is normally from 10 MB/s to 20 MB/s. High: Data synchronization takes a short period of time. This value is used when the service load is relatively light. The speed is normally from 20 MB/s to 70 MB/s. Highest: Data synchronization takes the shortest period of time. This value is used when the service load is light. The speed is normally above 100 MB/s. Custom: customized data synchronization speed. The value ranges from 1 MB/s to 1024 MB/s.
      Recovery Policy	Determines how data is synchronized after a fault is rectified. Automatic: The system automatically synchronizes data. Manual: Data must be synchronized manually.
      Initial Sync	Initial synchronization mode of local and remote resources. Automatic: The system automatically synchronizes data between local and remote resources upon pair creation. Manual: Data must be manually synchronized between local and remote resources.

   3. Configure parameters for the local and remote asynchronous remote replication CGs.

      Table 3-13 describes the parameters.

      Table 3-13 Asynchronous remote replication CG parameters

      Parameter	Description
      Sync Type	Determines how data is synchronized between primary and secondary resources. Possible values are as follows: Manual: Data must be manually synchronized between primary and secondary resources. Timed wait after sync begins: The system starts timing as soon as the latest synchronization begins. After the time specified in Interval is reached, the system automatically starts synchronizing data between primary and secondary resources again. NOTE: If the last synchronization has not finished after the time specified in Interval is reached, the system performs the next synchronization after the last synchronization finishes. Timed wait after sync ends: The system starts timing as soon as the latest synchronization ends. After the time specified in Interval is reached, the system automatically starts synchronizing data between primary and secondary resources again.
      Interval	Synchronization interval for Timed wait after sync begins and Timed wait after sync ends. NOTE: This parameter is available only when Sync Type is set to Timed wait after sync begins or Timed wait after sync ends.
      Speed	Data synchronization speed. Possible values are as follows: Low: Data synchronization takes a relatively long period of time. This value is used when the service load is heavy. The speed is normally from 0 MB/s to 5 MB/s. Medium: Data synchronization takes a relatively short period of time. This value is used when the service load is relatively heavy. The speed is normally from 10 MB/s to 20 MB/s. High: Data synchronization takes a short period of time. This value is used when the service load is relatively light. The speed is normally from 20 MB/s to 70 MB/s. Highest: Data synchronization takes the shortest period of time. This value is used when the service load is light. The speed is normally above 100 MB/s. Custom: customized data synchronization speed. The value ranges from 1 MB/s to 1024 MB/s.
      Recovery Policy	Determines how data is synchronized after an internal I/O error or a replication link fault is rectified. Possible values are as follows: Manual: Data must be synchronized manually. The CG enters the To be recovered state. Automatic: The system automatically synchronizes data. The CG enters the Synchronizing state.
      Link Compression	Indicates whether to enable link compression for data synchronization between local and remote resources. Enabling link compression saves the bandwidth of replication links and improves replication performance. Possible values are as follows: Yes No
      Initial Sync	Initial synchronization mode of local and remote resources. Automatic: The system automatically synchronizes data of the primary resource to the secondary resource upon pair creation. Ensure that data of the secondary resource is no longer needed or has been backed up. Manual: Data of the primary resource must be manually synchronized to the secondary resource. NOTE: This parameter is valid only when local asynchronous remote replication is configured.

      The value ranges of remote replication CG parameters depend on the local device. When you select another local device in asynchronous remote replication, such parameters will be reset to their default values.

6. Create remote resources.
   1. In the HyperMetro Remote Storage Pool drop-down list, select the storage pool to which the HyperMetro remote resource belongs.
   2. In the Async Remote Replication Remote Storage Pool drop-down list, select the storage pool to which the asynchronous remote replication remote resource belongs.
      • The storage system will create a remote LUN in HyperMetro Remote Storage Pool of the HyperMetro remote device and Async Remote Replication Remote Storage Pool of the asynchronous remote replication remote device respectively, create a HyperMetro pair and asynchronous remote replication pair for the selected local LUN and created remote LUN in the selected PG respectively, and then add the created pairs to a CG to create a DR Star trio.
      • When a remote LUN is created on the HyperMetro remote device and asynchronous remote replication remote device, the capacity and application type of the remote LUN is the same as those of the selected local LUN, the owning storage pools are HyperMetro Remote Storage Pool and Async Remote Replication Remote Storage Pool respectively, and default values are used for other parameters.

7. Select Advanced in the upper right corner and configure advanced DR Star trio parameters based on service requirements.

   Table 3-14 describes the parameters.

   Table 3-14 Advanced DR Star trio parameters

   Parameter	Description
   Switchover Policy	Policy of switching the status of the two asynchronous remote replication CGs between Normal and Standby when a fault occurs. Possible values are as follows: Manual: When a fault occurs, you need to manually switch the status of the two asynchronous remote replication CGs to rectify the fault. Automatic: When a fault occurs, the storage system automatically switches the status of the two asynchronous remote replication CGs based on specific fault conditions.
   Switchover Silent Time (Minutes)	When Switchover Policy is set to Automatic and a fault occurs, the storage system will automatically switch the status of the two asynchronous remote replication CGs if the fault persists after the switchover silent time expires. If the fault is rectified before the switchover silent time expires, the storage system will not perform the switchover. NOTE: This parameter is available only when Switchover Policy is set to Automatic.

8. Click Next.
9. Configure mappings for HyperMetro LUNs.
   • If the current PG contains only LUNs and does not support mapping, choose Services > Block Service > LUNs to configure the mapping for the LUNs after the DR Star trio is created.
   • The LUNs at both ends of a HyperMetro pair must be mapped to the same host. You can enable Map to Same Host or Host Group to quickly create the mapping for the LUNs at both ends.
   1. Enable Map to Same Host or Host Group.
      • If you want to map LUNs to different hosts, disable Map to Same Host or Host Group and configure the mappings for the local and remote LUNs separately.
      • When LUNs are mapped to the same host or host group, the initiator information of the hosts to which the HyperMetro LUNs are mapped must be the same on the local and remote storage systems.
      • If the local LUN has been mapped to a host, you only need to set Host Access Mode after enabling Map to Same Host or Host Group. If Map to Same Host or Host Group is disabled, you need to configure the mapping for the remote LUN separately.
   2. Select a host or host group to which you want to map the LUNs.

      In no host group is available, click Create. On the displayed dialog box, you can create a host group.

   3. (Optional) Select Local Port Group.

      After a port group is selected, LUNs in the LUN group use the ports of the port group to communicate with hosts in the host group. If no port group is selected, available ports are randomly used.

   4. Set Host LUN ID. Possible modes are Automatic or Manual. If you select Manual, specify a host LUN ID ranging from 0 to 4095.
   5. Specify Host Access Mode. Possible values are Load balancing or Asymmetric.

10. Click Next.

    A summary is displayed.

11. Confirm the DR Star trio information and click OK.

    Confirm your operation as prompted.

    You can click CG Parameters to view details of configured CG parameters.