Creating a Protected Group for LUNs

Prerequisites

• At least one production site has been created.
• At least one storage device has been added.
• LUNs in the backup (SAN) scenario must belong to the system vStore.

Context

• Protected objects in a protected group must reside on the same storage device.
• This section describes how to create protection for Huawei Distributed Block Storage volumes.

Procedure

1. In the menu bar, Choose Protection.
2. Click Create.
3. Select a protected object.
   1. Select Production Site and Disk Array.
   2. In LUN and Consistency Groups, select the protect object.
      • LUN

        If you want to protect one LUN only or multiple LUNs that reside in different remote replication consistency groups, set the protected object type to LUN.

      • Remote replication consistency group

        If you want to protect all LUNs of one remote replication consistency group, set the protected object type to Remote replication consistency group.

4. Click Next.
5. Set a protection policy.
   1. On the Protection Policy page, the system automatically matches supported protection policies. Select a protection policy based on your data protection solution.
      • When the synchronous Clone (SAN) DR technology is used, select Clone:Backup protection solution.
      • When the synchronous Backup (SAN) DR technology is used, select Backup:Backup protection solution.
      

      • If there are suitable protection policies, you can select a protection policy based on your data protection solution and modify the time policy of the protection policy.
      • If there is no suitable protection policy, check whether the storage devices used by protected objects have been configured as planned. If the storage devices have not been configured, configure them as planned. After configuration, perform the following operations: On the menu bar, select Resources. Select a node under the management server. In the site node, click Storage, in the line where the storage device resides, click Refresh to refresh the storage device information under the site. Then, recreate the protected group.
   2. Click Set to set the protection policy for the protected group.
      • For Clone:Backup protection solution:
        1. In the Protection Policy area, click Set to set the protection policy for the protected group.
        2. Click the Scheduling Policy tab. In the Time Policy area, set the time policy for the protected group. Table 1 lists related parameters.

           

           Table 1 Time policies

           Time Policy	Description
           On-demand scheduling	Manually starts protection tasks.
           Period-based scheduling	Automatically starts protection tasks based on a period set by the system. NOTE: To ensure data consistency, the execution timetable for a protected group policy template must be set. You are advised to set the execution time to off-peak hours. Tasks can be executed at multiple time points of a day, a week, or a month. Alternatively, at a specific time segment of a day, a week, or a month with a fixed frequency. It is recommended that the starting time of the validate period is set to a time later than the completion of the initial synchronization. If daylight saving time (DST) is enabled on the eReplication management server, a DR protection task whose trigger time point falls within the DST shift period cannot be executed at the scheduled time. Details are as follows: (UTC-08:00) Pacific Time (United States and Canada) is used as an example. The DST starts at 2016-03-12 02:00:00, and ends at 2016-11-06 02:00:00. If the start time of the protection policy falls within the first hour (2016-03-12 02:00:00 to 03:00:00) after the DST starts, for example, 2016-03-12 02:30:00, the protection group will be automatically executed with a delay of one hour, that is 2016-03-12 03:30:00. If the start time of the protection policy falls with the last hour (2016-11-06 01:00:00 to 02:00:00) before the DST ends, for example, 2016-11-06 01:30:00, the protection group will be executed after the DST ends for half an hour.

        3. When the Scheduling Policy is set to Period-based scheduling, in the Expected RPO area, if you select Enable PRO Requirement Satisfaction Check, the actual RPO is check against the configured RPO. If the actual RPO exceeds the expected RPO, the system generates an alarm, indicating that the RPO requirement is not satisfied.

           

           Expected RPO can be set to 0-31 days, 0-23 hours, and 5-59 minutes.

           

           If days and hours are not set, the Expected RPO is 15 minutes by default.

        4. Click the Clone Policy tab page to set the execution policy for the clone splitting. Table 2 shows description about parameters.

           

           Table 2 Description about the clone policies

           Execution Policy	Policy Description
           Delay the splitting after the protected group begins to be executed	By default, the clone splitting starts immediately after the data replication is complete.If you select Delay the splitting after the protected group begins to be executed, the splitting starts when the split delay time comes. NOTE: The value of Split Delay Time is not greater than 1410. If the split delay time comes, the data replication will be stopped even if it is incomplete and the clone splitting will start. If a user has configured a prescript or frozen script, the prescript or frozen script will be executed before splitting.
           Create a snapshot if the splitting fails	If the splitting fails, replace the clone copy with the consistency snapshot of the primary LUN. NOTE: If you deselect Create a snapshot if the splitting fails, the protected group will fail to be executed after the splitting fails.

        5. If Enable consistency protection is selected, the system runs the application freezing script on a specific host (or host group) to ensure replica data consistency when a protection task is being executed. After replicas are generated or applications are not unfrozen within the allowed freezing timeout duration, the system automatically runs the unfreezing script to ensure normal service operation.

           

        6. If Enable consistency protection is selected, select Application Host (Group) of the executed script and fill in Freezing Script, Unfreezing Script, Freezing Status Query Script, and Freezing Timeout.
           

           The scripts are not delivered with the eReplication. The script provider needs to ensure the correctness of the script. Before configuring a script, check whether the script is verified by tests.

        • Freezing Script: this script is used to unfreeze application I/Os.
        • Unfreezing Script: this script is used to check whether applications are frozen.
        • Freezing Status Query Script: this script is used to check whether applications are frozen.
        • Freezing Timeout indicates the maximum freezing duration supported by host services. The default value is 60 seconds.
        7. Click OK.
        8. In the Storage Configuration area, select the resource pool configuration as show in Table 3.

           Table 3 Resource pool configuration

           Configuration	Description
           Default configuration	Please select or create the resource pool at first, the system will establish clone replationship based on LUNs in resource pool. If a data protection service (for example, snapshots) has been created for a matched resource, the clone relationship may fail to be created. The protected object (clone primary LUN) has a one-to-one relationship with the matched resource (clone secondary LUN).
           Manual configuration	Manually select the resource pool, if not, click Create, the system will establish clone replationship based on LUNs in resource pool. The protected object (clone primary LUN) has a one-to-one relationship with the matched resource (clone secondary LUN).

      • For Backup:Backup protection solution:
        1. In the Quick Backup area of Protection Policy, click Set to set the protection policy for the protected group.
        2. Click Enable Quick Backup and select Backup Type.
           • Snapshot: The read and write permissions of the generated snapshot are readable and writable.
           • HyperCDP: The read and write permissions of the generated snapshot are readable.
             

             • If you have purchased the HyperCDP license, HyperCDP is recommended. HyperCDP provides high-density protection, ultra-large specifications, and lossless performance.
             • Create a second-level protected group. BCManager creates a scheduled plan on the storage array. The scheduled plan can be managed only by BCManager. You cannot delete the scheduled plan from the storage array.
        3. Click the Scheduling Policy tab. In the Time Policy area, set the time policy for the protected group. Table 4 lists related parameters.

           

           Table 4 Time policies

           Time Policy	Description
           On-demand scheduling	Manually starts protection tasks.
           Period-based scheduling	Automatically starts protection tasks based on a period set by the system. NOTE: To ensure data consistency, the execution timetable for a protected group policy template must be set. You are advised to set the execution time to off-peak hours. Tasks can be executed at multiple time points of a second, a minute, an hour, a day, a week, or a month. Alternatively, at a specific time segment of a second, a minute, an hour, a day, a week, or a month with a fixed frequency. When Backup Type is set to Snapshot and Time Period is set to Second, the minimum interval for executing protected groups is 30 seconds. When Backup Type is set to HyperCDP and Time Period is set to Second, the minimum interval for executing protected groups is as follows: OceanStor Dorado V3: 10 seconds OceanStor Dorado V6: 3 seconds It is recommended that the starting time of the validate period is set to a time later than the completion of the initial synchronization. If daylight saving time (DST) is enabled on the eReplication management server, a DR protection task whose trigger time point falls within the DST shift period cannot be executed at the scheduled time. Details are as follows: (UTC-08:00) Pacific Time (United States and Canada) is used as an example. The DST starts at 2016-03-12 02:00:00, and ends at 2016-11-06 02:00:00. If the start time of the protection policy falls within the first hour (2016-03-12 02:00:00 to 03:00:00) after the DST starts, for example, 2016-03-12 02:30:00, the protection group will be automatically executed with a delay of one hour, that is 2016-03-12 03:30:00. If the start time of the protection policy falls with the last hour (2016-11-06 01:00:00 to 02:00:00) before the DST ends, for example, 2016-11-06 01:30:00, the protection group will be executed after the DST ends for half an hour.

        4. When the Scheduling Policy is set to Period-based scheduling, in the Expected RPO area, if you select Enable PRO Requirement Satisfaction Check, the actual RPO is check against the configured RPO. If the actual RPO exceeds the expected RPO, the system generates an alarm, indicating that the RPO requirement is not satisfied.

           

           Expected RPO can be set to 0-31 days, 0-23 hours, and 5-59 minutes.

           

           If days and hours are not set, the Expected RPO is 15 minutes by default.

        5. Click the Reservation Policy tab. Set Latest duplicate and the duplicate retention policy. Table 5 describes related parameters.

           

           Table 5 Retention policies

           Retention Policy	Description
           Latest duplicate	The number of duplicates cannot exceed the maximum number of snapshots that can be taken for a storage resource such as a LUN or file system.
           Duplicate retention	The duplicate retention policy defines the retention policy of duplicates generated during the protected group protection. When the system starts duplicate maintenance, expired and invalid duplicates will be deleted based on the duplicate retention policy. By default, the time to maintain duplicates is the 39th minute of every hour. You can set the minimum number of duplicates to be retained. The system will not delete valid duplicates until the number of invalid duplicates exceeds the minimum number of duplicates you set. The value range for a daily policy is 0–365. The default value is 0, meaning to retain no duplicates. The value range for a weekly policy is 0–52. The default value is 0, meaning to retain no duplicates. The value range for a monthly policy is 0–60. The default value is 0, meaning to retain no duplicates. When determining the number of retained duplicates, consider the following: Data importance and DR requirements. If data of the latest five months must be retained, you are advised to set the retention period by month. Available storage space of a storage device. If the available space of a storage device is sufficient, you are advised to retain more duplicates that are more important. NOTE: For example, if the current time is 2017/4/11 08:40:00, configure the protected group as following: Set the execution policy to be performed at every hour exactly. Set the retention policy to keep five latest duplicates, three daily duplicates, two weekly duplicates, and one monthly duplicate. If the protected group is under the automatically scheduled protection for a long time, the duplicates retained are as follows after the duplicate maintenance is complete at the current time: Latest duplicates were generated at: 2017-04-11 08:00, 2017-04-11 07:00, 2017-04-11 06:00, 2017-04-11 05:00, and 2017-04-11 04:00. Daily duplicates are generated at: 2017-04-10 23:00, 2017-04-09 23:00, and 2017-04-08 23:00. Weekly duplicates were generated at: 2017-04-09 23:00 and 2017-04-02 23:00. The monthly duplicate was generated at: 2017-03-31 23:00. NOTE: If the duplicate maintenance is not triggered, or daily, weekly, or monthly duplicate retention is configured, the number of retained duplicates may exceed the number of latest duplicates being retained.

        6. If Enable consistency protection is selected, the system runs the application freezing script on a specific host (or host group) to ensure replica data consistency when a protection task is being executed. After replicas are generated or applications are not unfrozen within the allowed freezing timeout duration, the system automatically runs the unfreezing script to ensure normal service operation.

           Select Enable consistency protection, and then select Application Host (Group) for which the script needs to be executed.

           If you select System script, perform the following operations:

           1. Select the system script type corresponding to the service host (group).
           2. Set script parameters.
              • On the right of Freezing Script, click Configuring Script Parameters to set parameters for the freezing script. Freezing Script: Freezing Script: this script is used to freeze application I/Os.
              • On the right of Unfreezing Script, click Configuring Script Parameters to set parameters for the unfreezing script. Unfreezing Script: this script is used to unfreeze application I/Os.
              • On the right of Freezing Status Query Script, click Configuring Script Parameters to set parameters for the freezing status query script. Freezing Status Query Script: this script is used to check whether applications are frozen.
              

              • Common parameters are applicable to all scripts. Step parameters are applicable only to the current script.
              • Parameter names and values in the scripts cannot contain special characters. Otherwise, executing the scripts may fail.

                Special characters include ~!@#$%*-_=+[{}];:\,./?.

           3. On the right of Freezing Status Query Script, click Configuring Script Parameters to set parameters for the freezing status query script. Freezing Status Query Script: this script is used to check whether applications are frozen.
           If you select Customized script, perform the following operations:

           1. Choose Unfreezing Script, Freezing ScriptFreezing Status Query Script, and configure script parameters.
              

              • A self-defined script is not provided by eReplication, so the script provider must ensure the script correctness. Before configuring the script, ensure that the script has been verified.
              • Parameter names and values in the scripts cannot contain special characters. Otherwise, executing the scripts may fail.

                Special characters include ~!@#$%*-_=+[{}];:\,./?.

              • On the right of Freezing Script, click Configuring Script Parameters to set parameters for the freezing script. Freezing Script: Freezing Script: this script is used to freeze application I/Os.
              • On the right of Unfreezing Script, click Configuring Script Parameters to set parameters for the unfreezing script. Unfreezing Script: this script is used to unfreeze application I/Os.
              • On the right of Freezing Status Query Script, click Configuring Script Parameters to set parameters for the freezing status query script. Freezing Status Query Script: this script is used to check whether applications are frozen.
           2. Freezing Timeout indicates the maximum freezing duration supported by host services. The default value is 60 seconds.
        7. Click OK.
           • When System script is selected, In the Warning dialog box that is displayed, read the content of the dialog box carefully and select I have read and understood the consequences associated with performing this operation.. Click OK.
           • When Customized script is selected, the system will automatically deliver commands.

6. Click Next.
7. Set Name and Description of the protected group.
   • Name: contains 4 to 32 characters, including letters, digits, underscores (_), and hyphens (-), but cannot start with a hyphen (-).
   • Description: contains 0 to 255 characters.

8. When the Backup (SAN) DR technology is used, if you do not want to manually create a recovery plan for the protected group, select Automatically create a recovery plan after creating protected groups at the lower left corner.
9. Click Finish.
10. Click OK.

Related Operations

• If the protected objects of a protected group or their used storage devices change. On the menu bar, select Resources. And refresh resources or storage devices where the protected objects reside. Then go to the protected group page and refresh protected objects of the protected group by clicking More > Refresh. After the command for refreshing information is sent, you can view details about the command execution in Background Task.
  

  If a recovery plan has been created for a protected group, you can refresh protected objects only when the recovery plan status is Ready, Clear completed, Rollback completed, or Reprotection completed.

• To ensure that information about protected groups is refreshed successfully, you must refresh information about storage devices and hosts at both the production site and DR site.
  

  If a protected group uses backup (SAN), a snapshot copy being used by a recovery plan cannot be deleted. To delete such a snapshot copy, wait until the recovery plan finishes clearing.