Disk mirroring

In a disaster recovery context, mirroring data over long distance is referred to as storage replication.

Synchronous writing typically achieves a recovery point objective (RPO) of zero lost data.

Typically, mirroring is provided in either hardware solutions such as disk arrays, or in software within the operating system (such as Linux mdadm and device mapper).

[1][2] Additionally, file systems like Btrfs or ZFS provide integrated data mirroring.

Under certain circumstances, this can significantly improve performance as the system can choose for each read which disk can seek most quickly to the required data.