Metro Mirror

You can configure an IBM® i high availability solution that uses Metro Mirror. Metro Mirror maintains a consistent copy of data between two IBM System Storage® external storage units.

Metro Mirror, when used with cluster technology, provides a high availability and disaster recovery solution. Like geographic mirroring, this technology also mirrors data stored in independent disk pools. However, with Metro Mirror, disks are located on IBM System Storage external storage units. Mirroring occurs from the source external storage units, which are usually located at the production site, to a set of target storage units, which are usually at the backup site. The data is copied between the external storage units to provide availability for both planned and unplanned outages.

Metro Mirror is a function of the external storage unit where the target copy of a volume is constantly being updated to match changes that are made to a source volume. It is typically used for applications that cannot suffer any data loss in the event of a failure. The source and target volumes can be on the same external storage unit or on separate external storage unit. In the case of separate units, the target storage unit can be located at another site up to 300 kilometers (186 miles) away. However, there might be performance implications when using synchronous communications over this distance and it might be more practical to consider one shorter to minimize the performance impact.