Dell PowerStore Protecting Your Data

Metro witness

As of PowerStore operating system version 3.6, you can add a witness server to metro protection to provide protection from single failure scenarios.

The witness server is a passive third party that is installed on a stand-alone host (preferably in another data center). When failure occurs, the local and remote PowerStore systems contact the witness server and request to fracture the metro session. The witness then determines which system remains accessible to hosts and continues to service I/Os. If possible, the witness gives precedence to the PowerStore system that was assigned with the preferred role. Adding the witness to a metro session provides protection from single failure scenarios, including preferred system failures which are not handled without a witness.

The witness service is simple and does not maintain critical data that cannot be re-created. As such, there is no need to backup, save, or recover the witness, and it can be removed and reinstalled whenever recovery is required.