Basic Concepts

Protected Object

For customers, the protected objects are LUNs or protection groups. That is, HyperMetro is configured for LUNs or protection groups for data backup and disaster recovery.

• Data protection can be implemented for each individual LUN.
• Data protection can be implemented for a protection group, which consists of multiple independent LUNs or a LUN group.

Protection Group (PG) and LUN Group

A LUN group can be directly mapped to a host for the host to use storage resources. You can group LUNs for different hosts or applications.

A protection group (PG) applies to data protection with consistency groups. You can plan data protection policies for different applications and components in the applications. In addition, you can enable unified protection for LUNs used by multiple applications in the same protection scenario. For example, you can group the LUNs to form a LUN group, map the LUN group to a host or host group, and create a protection group for the LUN group to implement unified data protection of the LUNs used by multiple applications in the same protection scenario.

HyperMetro Domain

A HyperMetro domain allows application servers to access data across DCs. It consists of a quorum server and the local and remote storage systems.

HyperMetro Pair

A HyperMetro pair is created between a local and a remote LUN within a HyperMetro domain. The two LUNs in a HyperMetro pair have an active-active relationship. You can examine the state of the HyperMetro pair to determine whether operations such as synchronization, suspension, or priority switchover are required by its LUNs and whether such an operation is performed successfully.

HyperMetro Consistency Group (CG)

A HyperMetro consistency group (CG) is created based on a protection group. It is a collection of HyperMetro pairs that have a service relationship with each other. For example, the service data, logs, and change tracking information of a medium- or large-size database are stored on different LUNs of a storage system. Placing these LUNs in a protection group and then creating a HyperMetro consistency group for that protection group can preserve the integrity of their data and guarantee write-order fidelity.

Relationships Between LUNs, Protection Groups, HyperMetro Pairs, and HyperMetro Consistency Groups

Creating a HyperMetro pair for an individual LUN:

Creating a HyperMetro consistency group for a protection group (formed by multiple independent LUNs)

Creating a HyperMetro consistency group for a protection group (formed by a LUN group)

Dual-Write

Dual-write enables the synchronization of application I/O requests with both local and remote LUNs.

DCL

Data change logs (DCLs) record changes to the data in the storage systems.

Synchronization

HyperMetro synchronizes differential data between the local and remote LUNs in a HyperMetro pair. You can also synchronize data among multiple HyperMetro pairs in a consistency group.

Pause

Pause is a state indicating the suspension of a HyperMetro pair.

Force Start

To ensure data consistency in the event that multiple elements in the HyperMetro deployment malfunction simultaneously, HyperMetro stops hosts from accessing both storage systems. You can forcibly start the local or remote storage system (depending on which one is normal) to restore services quickly.

Preferred Site Switchover

Preferred site switchover indicates that during arbitration, precedence is given to the storage system which has been set as the preferred site (by default, this is the local storage system). If the HyperMetro replication network is down, the storage system that wins arbitration continues providing services to hosts.

FastWrite

FastWrite uses the First Burst Enabled function of the SCSI protocol to optimize data transmission between storage devices, reducing the number of interactions in a data write process by half.