Global Mirror is an IBM technology that provides data replication over extended distances between two sites for business continuity and disaster recovery.
It replicates the data asynchronously and also forms a consistency group at a regular interval allowing a clean recovery of the application.
Global mirror periodically pauses updates of the primary volumes and swaps change recording bitmaps.
[3] Global Mirror can be combined with a wide area network clustering product like Geographically Dispersed Parallel Sysplex (GDPS), HACMP/XD, or IBM TotalStorage Continuous Availability for Windows to provide for automated failover between sites.
This combined solution provides lower recovery time objective (RTO), because it allows most applications to automatically resume productive operation in 30–600 seconds.