Creating a Synchronous Remote Replication Consistency Group

Creating a synchronous remote replication consistency group enables you to synchronize data in real time, ensuring maximum data consistency between primary and secondary sites and minimal data loss in the event of a disaster. Synchronous remote replication is used in DR scenarios where the local and remote storage devices are close to each other or the network bandwidth is high.

Prerequisites

A replication cluster has been configured and a remote device has been added.
Role of a remote replication pair to be added to a consistency group is Primary.
The secondary resources in remote replication pairs to be added to a consistency group must be from the same storage device.
Replication Mode of a remote replication pair to be added to a consistency group must be the same as that of the consistency group.

Procedure

Choose Data Protection > Protection Entity > Protection Group > Remote Replication Consistency Group.
Click Create.
The Create Remote Replication Consistency Group page is displayed on the right.

Configure basic information about the consistency group. Table 1 describes related parameters.

**Table 1** Consistency group parameters
Parameter	Description
Name	Name of the consistency group. [Value range] The name must be unique. The name can only contain digits, letters, underscores (_), and hyphens (-), and must start with a digit or letter. The name contains 1 to 31 characters.
Replication Mode	Set the replication mode of the remote replication consistency group to Synchronous.
Replication Cluster	Replication cluster to which the consistency group belongs.
Remote Device	Storage device to which the secondary resource of a remote replication pair to be added to the consistency group belongs.

(Optional) Add a remote replication pair to the remote replication consistency group.
1. Select Add Remote Replication Pair.
2. In the Available Remote Replication Pairs area, select one or more remote replication pairs and they are added to the Selected Remote Replication Pairs area on the right.

Click Advanced to set advanced properties of the remote replication consistency group. Table 2 describes related parameters.

**Table 2** Advanced remote replication consistency group parameters
Parameter	Description
Speed	Data synchronization speed of the remote replication consistency group. The value ranges from 1 MB/s to 1024 MB/s (or 1024 KB/s to 1,048,576 KB/s). During initial synchronization, the recommended rate is 100 MB/s or higher. During incremental synchronization, if the service load is heavy, the recommended rate is 0 MB/s to 20 MB/s. During incremental synchronization, if the service load is relatively heavy, the recommended rate is 20 MB/s to 70 MB/s. During incremental synchronization, if the service is idle, the recommended rate is 100 MB/s or higher. The default value is 32 MB/s.
Recovery Policy	Whether the system automatically synchronizes data after a remote replication fault is rectified. The default value is Automatic. [Value range] Automatic: The previous ongoing tasks automatically resume immediately after the remote replication fault is rectified. Manual: The value of Running Status changes to To be recovered after the remote replication fault is rectified. In this case, you can check the system and then determine whether to resume the previous ongoing tasks manually.
I/O Timeout Threshold of Secondary Resource	If data fails to be written from a primary resource to a secondary resource after the timeout, the remote replication consistency group enters the interrupted state.
Timeout Threshold (second)	The timeout threshold ranges from 15s to 120s. NOTE: This parameter is available only when I/O Timeout Threshold of Secondary Resource is enabled.

Click OK.