The NetApp MetroCluster Mediator is a software component that runs on a dedicated Linux host located at a third site, separate from the two main MetroCluster data centers. Its primary role is to act as a witness or quorum device to enable Automatic Unplanned Switchover (AUSO). By monitoring the health of both MetroCluster sites, it can help the surviving site make an informed decision to take over operations automatically if the other site and the inter-site links fail, thus preventing a split-brain scenario.

The ONTAP Controller is the primary storage system hardware/software, not a separate mediation component on a Linux host.

Cluster Scheduler is an internal ONTAP process for managing scheduled jobs and has no role in MetroCluster mediation.

Disk Manager is a generic term; disk management is an integrated function of the ONTAP operating system.

1. NetApp, Inc. (2023). Concepts in MetroCluster. NetApp Product Documentation. The section on MetroCluster components describes the Mediator: "A third-party component, the ONTAP Mediator, can be installed on a Linux server to monitor the MetroCluster configuration and assist in automated switchover."

2. NetApp, Inc. (2023). Install or upgrade MetroCluster Mediator. NetApp Product Documentation. This guide provides instructions for deploying the Mediator service on a supported Linux host (RHEL or CentOS).