Arbitration service Overview

What is arbitration service?

The arbitration service is a new feature introduced in OceanBase Database V4.1. The arbitration service not only solves the problem of increased response time that occurs when a replica in the primary region fails in the deployment mode of three IDCs across two regions, but also reduces the cross-region bandwidth overheads and minimizes the costs of the third IDC.

The arbitration service maintains arbitration members corresponding to log streams of a tenant. An arbitration member has the following characteristics:

• An arbitration member votes in leader election, Paxos Prepare, and member group change, but does not participate in Paxos Accept.

• An arbitration member does not store logs and has no MemTables or SSTables. Therefore, it consumes minimal bandwidth, memory, disk, and CPU resources.

• An arbitration member cannot be elected as a leader to provide services.

If half of the full-featured replicas in a cluster fail, which means that the logs on the majority of replicas cannot be synchronized, the arbitration service enables the cluster to automatically downgrade to restore the database services, with a recovery point objective (RPO) of 0. After the failed replicas are recovered, the cluster automatically upgrades and restores the original replica list.

Prerequisites

Make sure that you have the following permissions:

• Resource Permissions: Arbitration Service Read-only permission
• Menu Permissions: Permission on the Overview menu of Clusters

View the arbitration service list

Log on to the OceanBase Cloud Platform (OCP) console. In the left-side navigation pane, click Clusters to go to the Cluster Overview page. To view the cluster overview data, the current logged-on user must have the management permission or read-only permission on clusters. On the Overview page, click the ... icon and choose Arbitration Service Management to go to the Arbitration Service List page.

The Arbitration Service List page displays information about each arbitration service in the following columns: Host, Tag, Service Port, Description, Version, Associated Cluster, Created At, and Status. You can query an arbitration service by host IP address or cluster name.

• You can click the IP address of a host to go to the host monitoring page. For more information, see View host performance and View host resources.

• You can click the name of a cluster associated with an arbitration service to go to the Overview page of the cluster. For more information, see Overview page of a cluster.

• You can filter arbitration services by Status.

Manage arbitration services

You can also create, stop, start, upgrade, restart, and delete an arbitration service. For more information, see Create an arbitration service, Stop an arbitration service, Start an arbitration service, Upgrade an arbitration service, Restart an arbitration service, Delete an arbitration service.