DR Test/Clearance

After the DR environment is configured, periodic tests can improve the reliability of the DR environment and avoid configuration problems and environment changes which cause the DR switchover to fail and services not to recover quickly through the DR system. DR tests are implemented using snapshot mappings at the DR site to verify the availability of data or snapshots replicated to the Remote DR center. The test process has no adverse impact on the production site. After a test is complete, the test data generated at the DR site needs to be cleared and resources need to be restored to the status before the test to facilitate future DR or planned migration.

Prerequisites

The production center communicates with the DR center properly.
At least one recovery plan has been created on eReplication.
The DR host to be tested has been prepared in the DR center.
To database applications, all check items related to DR environments are passed. For details about the checklist, see Oracle, IBM DB2, Microsoft SQL Server, VMware VMs.
If information about storage devices, hosts, or VMs is modified at either the production or DR site, manually refresh the information. For details, see Refreshing Resource Information.

Context

Data testing in the Remote DR center is used to verify data availability. During the test, the data stored at the DR site is the latest data synchronized using remote replication. The test is to create an instant snapshot for the remote replication DR LUN and map the snapshot to the DR host. Figure 1 shows the test. After the test is complete, use the one-click cleanup function provided by eReplication to clear test data in a timely manner. That is, the system automatically deletes the mapping between the instant snapshot and DR host, and delete the instant snapshot.

Figure 1 DR test

You are advised to configure application-based protection policies for Oracle, SQL Server, DB2 and SAP HANA to support one-click testing.
You are advised to configure LUN-based protection policies for other applications to enable automatic test configuration on the storage system. For this purpose, you need to manually or use self-defined scripts to start and test applications.
In a DR test, snapshots at the DR site can only be mapped to the initiators. The port mapping mode is not supported.

The DR test is a major operation. During the DR test, pay attention to the following points:

Before testing a protected group whose protection type is database, ensure that all database connections at the DR site are disconnected.
During the DR test, system and service administrators are not allowed to perform any maintenance operation.
Test data must be cleared before the next DR test.
After a test is complete, clear the test data as soon as possible. If the eReplication environment is recovered after a network failure or environment failure during the test, performing clearing may leave some data uncleared. In such situations, manually clear the test data, and then perform clearing again.

Procedure

Log in to eReplication in the DR center.
Test a recovery plan.
1. On the menu bar, choose Utilization > Data Restore.
2. Select the recovery plan to be tested, and then choose More > Test in the Operation area.
If Huawei UltraPath has been installed on the Linux-based DR host, ensure that I/O suspension time is not 0, and virtual devices generated by UltraPath have corresponding physical devices. For more details, see the OceanStorUltraPath for Linux V100R008C00 User Guide.
- Select a DR host.
- Select a DR Copy.
- Click Test.

After the test is complete, verify that applications are started at the remote DR site.
Verify that applications can be started and data read and write operations can be performed. If an application fails to be started or data read and write operations fails to be performed, contact Huawei technical support engineers.
- If the protection policies are based on applications, check whether the applications are started successfully and data can be read and written properly.
- If the protection policies are based on LUNs, log in to the application host at the DR site, scan for disks, and start applications. Then check whether the applications are started successfully and data can be read and written properly.
- After the DR test, if the protected object type is VMware VM, the VM name registered on the test host is in the format of Protected VM name_4-digit random number_Snapshot_Recovery plan name.
- You can use self-developed scripts to scan for disks, start applications, and test applications.
The test data generated at the DR site needs to be cleared and resources need to be restored to the status before the test to facilitate future DR or planned migration.

Before clearing a protected group whose protection type is database, ensure that all database connections at the DR site are disconnected.
1. Select the recovery plan whose data you want to clear. Choose More > Clear on the Operation list.
  
  In the Oracle application, the cluster is not stoppd by default. To stop the cluster, you need to open the configuration for stopping the cluster and then perform the next step. For details about how to stop the cluster, see 4.2 Stopping the Oracle Cluster.
2. Carefully read the contents of the dialog box and then click OK.