Disk mirroring

Definition
Disk mirroring is

"the duplication of data on separate disks in real time to ensure its continuous availability, currency and accuracy. Disk mirroring can function as a disaster recovery solution by performing the mirroring remotely. True mirroring will enable a zero recovery point objective. Depending on the technologies used, mirroring can be performed synchronously, asynchronously, semi-synchronously, or point-in-time."