- IBM Global Mirror
Global Mirror is an
IBM technology that providesdata replication over extended distances between two sites forbusiness continuity anddisaster recovery . If adequate bandwidth exists, Global Mirror provides anrecovery point objective (RPO) of as low as 3-5 secondsFact|date=August 2007 between the two sites at extended distances with no performance impact on the application at the primary site. It replicates the data asynchronously and also forms a consistency group at a regular interval allowing a clean recovery of the application.The two sites can be on separate continents or simply on different utlility grids. IBM also provides a synchronous data replication called
Metro Mirror , which is designed to support replication at "Metropolitan" distances of (normally) less than 300 km Fact|date=August 2007.Global Mirror is based on existing IBM
Copy Services functions:Global Copy andFlashCopy . Global Mirror periodically invokes a point-in-time copy at the primary site, at regular intervals, without impacting the I/O to the source volumes. Then it transfers the copy to the recovery site. By grouping many volumes into one Global Mirror session multiple volumes may be copied to the recovery site simultaneously while maintaining point-in-time consistency across those volumes.Global Mirror can be combined with a wide area clustering product like
Geographically Dispersed Parallel Sysplex (GDPS),HACMP/XD , orCAW to provide for automated failover between sites. This combined solution provides lowerrecovery time objective (RTO), because it allows most applications to automatically resume productive operation in 30-600 seconds.The Global Mirror function is available on IBM's enterprise storage devices including the
DS8100 , theDS8300 , theDS6800 , the Enterprise Storage Server Models 800 and 750, midrange storage servers DS4000 family and theIBM SAN Volume Controller .
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