Rapid digital technology advancement across many various industries is highlighting the critical role of data in enterprise success. As a result, customers are becoming more stringent in their storage systems requirements. Although some storage devices promise extremely high stability, they still fail to prevent irrecoverable damage to production systems in the event of a natural disaster.
Therefore, in order to ensure continuity, recoverability, and high reliability of service data, both remote application technology and remote DR solutions become an essential requirement.
BACKGROUND INFORMATION
Definition
HyperReplication is a core technology for remote DR and backup of data.
Asynchronous remote replication
In this mode, data is periodically synchronized between two storage systems in order to minimize service performance deterioration caused by the latency of long-distance data transmission.
This section describes basic concepts related to HyperReplication, including pair, consistency group, synchronization, splitting, primary/secondary switchover, data status, and writable secondary LUN.
To enable service data backup and recovery within the secondary storage system, a remote replication task is implemented in four phases, as shown in Figure 1:
Figure 1. Implementation of a remote replication task
SERVICE SWITCHOVER
Service switchover via remote replication
Services can run on the secondary storage system only when the following conditions are met:
historical service data exist in the secondary storage system;
services on the production host have also been configured on the standby host;
the secondary storage system allows a host to access a LUN in a LUN group mapped to the host.
When a disaster occurs at the primary site, the remote replication links between the primary LUN and the secondary LUN go down. If this occurs, an administrator needs to manually change the access permission of the secondary LUN to 'writable' in order to enable a service switchover.
Figure 1-4 shows how a service switchover is implemented through remote replication.
Figure 1-4. Service switchover through remote replication
APPLICATION SCENARIOS
Backup and DR
In central backup and DR scenarios, service data distributed in different locations is backed up to the same site for centralized management. When a disaster occurs at a service site, the central backup site can take over services from the service site and recover data.
Figure 1-8 shows a central backup and DR scenario.
Figure 1-8. Central backup and DR
Functions of remote replication are as follows:
collects data from service sites 01 to n, takes a snapshot of a secondary LUN and maps the secondary LUN to a host. The snapshot can be used for data analysis and data mining;
allows the central backup site to take over services when any service site (01 to n) encounters a disaster and switches services back to the service site when the site recovers;
implements real-time backup (using the synchronous remote replication mode) between service site 01 and the central backup site that is 500 m away from service site 01. Performs replication tasks (using the asynchronous remote replication mode) between service site 02 and the central backup site that is 500 km away from service site 02.
