CM Supporting Two-Node Deployment

Availability

This feature is available since MogDB 3.1.0.

Introduction

The main goal of this feature is to improve the performance and reliability of CM cluster management components in a distributed environment. Specifically, by improving the DCF distributed consensus framework, the algorithm can be optimized, the network communication overhead can be reduced, and the fault-tolerance mechanism can be added, etc., so as to improve the data consistency guarantee.

Benefits

CM Cluster is a database cluster solution with high availability. By supporting two-node deployment and introducing third-party gateway IPs as arbitration nodes, CM Cluster is able to realize automatic failover and self-arbitration mechanisms to ensure data security and stability. CM Cluster maintains data continuity and availability, both in high load environments and in the event of a failure.

Overall, CM Cluster provides users with a high-availability database cluster solution by supporting two-node deployment and introducing third-party gateway IPs as arbitration nodes. It ensures data security and stability, reduces users' administrative work, and provides users with reliable database services by automatically switching over and recovering when failures occur.

Description

In the two-node deployment architecture, a third-party gateway IP is introduced as an arbitration node, and the CM cluster management component realizes a self-arbitration mechanism based on majority. When the cluster network state is normal, when any party in the CM master and backup instances initiates a voting election, as long as it is connected to the gateway IP, it will increase the number of votes it already has by 1, so as to achieve the purpose of majority decision-making. This mechanism ensures that under normal network conditions, the master and backup instances in the cluster can conduct elections and reach agreement, ensuring the stability and reliability of the cluster.

When the cluster network state is abnormal, once any party in the CM master and backup instances finds that it can only communicate with the gateway IP, it is considered that the opposite end may have a failure. The host side will perform the standby offline process, i.e., remove the standby from the cluster to avoid data inconsistency or conflict. The standby side will decide whether to perform automatic failover based on the configuration items, i.e., the standby machine will be switched to the host to ensure data continuity and availability.

This self-arbitration mechanism can effectively cope with the need for failover under abnormal network conditions. By determining the connectivity with the IP of the third-party gateway, the master and backup instances can quickly respond to network failures and make decisions based on the number of existing votes. Such a mechanism ensures cluster availability and data security, providing users with reliable database services.

Related Pages

Cluster Management, CM supports two-node deployment，CM Fault