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Sun Cluster Geographic Edition Overview

Data Replication

Data replication enables controlled migration of production services from a primary cluster to a secondary cluster either in the event of a disaster or as part of a planned procedure. Data is continuously replicated from the primary cluster to the secondary cluster either synchronously or asynchronously, or a combination of both, depending on the recover point objectives of the application services that are supported by the clusters.

The Sun Cluster Geographic Edition software supports the following software for data replication:

The Sun StorEdge Availability Suite 3.2.1 software uses a host-based data replication facility which replicates data at the file system or logical volume level within the operating system. The Hitachi TrueCopy software and EMC Symmetrix Remote Data Facility software use a storage-based data replication facility which replicates data at the storage system level and provides a transparent service to applications.

Sun Availability Suite Software

The Sun Availability Suite Software is a host-based replication facility that replicates disk volumes between geographically separated primary clusters and secondary clusters in real time. Remote mirror replication enables data from the master volume of the primary cluster to be replicated to the master volume of the geographically separated secondary cluster through a TCP/IP connection. A remote mirror bitmap tracks differences between the master volume on the primary disk and the master volume on the secondary disk.

The remote mirror software continually replicates the data to remote sites while your applications are accessing the data volumes. You can also manually update the data on the secondary site volume by issuing a command to synchronize the primary and secondary site volumes. You can also restore data from the secondary volume to the primary volume by issuing a command to reverse-synchronize the volumes. For more information about the Sun Availability Suite software, see the product documentation.

Hitachi TrueCopy Software

The Hitachi TrueCopy software is a storage-based replication facility that provides a host-independent data replication for geographically separated clusters. Hitachi TrueCopy software enables the primary volumes to remain online for all hosts and while processing both read and write I/O operations. If a disaster or system failure occurs, the secondary copy of the data can be run for a recovery with minimal loss of data. For more information about the Hitachi TrueCopy software, see the product documentation.

EMC Symmetrix Remote Data Facility Software

The EMC Symmetrix Remote Data Facility software provides remote storage replication for disaster recovery and ensures data and systems availability through remote site failover. EMC Symmetrix Remote Data Facility devices are configured in pairs. The mirroring relationship between the pairs becomes operational as soon as the EMC Symmetrix Remote Data Facility links are online. The EMC Symmetrix Remote Data Facility global memory stores information about the pair state of operating EMC Symmetrix Remote Data Facility devices. For information about the EMC Symmetrix Remote Data Facility software, see the product documentation.

Resource Groups

Resource groups and device groups enable the Sun Cluster Geographic Edition software to manage data replication and takeover between clusters. You can also configure a protection group to replicate data from a primary cluster to a secondary cluster. For more information about configuring data replication, see the guide for the data replication product you are using:

Replication Resource Groups

The Sun Cluster Geographic Edition software extends Sun Cluster resource management features to integrate the data replication products. When you configure a protection group, the Sun Cluster Geographic Edition software creates replication resource groups for monitoring and controlling data replication.

Device Groups

A device group is a hardware resource that Sun Cluster manages. A device group is a type of global device that the Sun Cluster software uses to register volume manager disk groups. The Sun Cluster Geographic Edition software configures Sun Cluster device groups to include replication. For information about configuring device groups in Sun Cluster, see the guide for the data replication product you are using: