Arbiter
Arbiter
The arbiter is an independent system hosting an ISCAgent with which the failover members of a mirror maintain continuous contact, providing them with the context needed to safely make failover decisions when they cannot communicate directly. A single arbiter can serve multiple mirrors, but a single mirror can use only one arbiter at a time. Use of an arbiter is not required, but is strongly recommended as it significantly increases the range of failure scenarios under which automatic failover is possible.
![The arbiter is not part of the mirror, but connects to the failover members over the network, like the mirror's clients.](images/gha_mirror_failovers_plus_arbiter.png)
The arbiter plays no role in failover mechanics when the backup is not active.
Configuring a system as arbiter involves minimal software installation and does not require that InterSystems IRIS be installed. The arbiter uses minimal system resources and can be located on a system that is hosting other services, or even a workstation. The primary requirement concerning the arbiter is that it must be located and configured to minimize the risk of unplanned simultaneous outage of the arbiter and a single failover member; see Locating the Arbiter to Optimize Mirror Availability for more information.