Since the email system was invented in the 1980s and with the rapid development of the Internet, emails have become the most popular inter-organization communication channel in the business environment. Businesses must continue operating especially during moments of downtime or system failures. High availability is the ability for a system to operate continuously without failing during periods of loss of services. It is one of the basic requirements to consider when choosing an email system so that it can maintain availability and reduce mail loss.

If you choose to build a high-availability email system, you will encounter problems such as high setup costs, overly complex systems, and management issues. There are two ways to achieve HA for our email services, MailPlus High Availability (HA) and Synology High Availability (SHA). MailPlus HA cluster architecture is specifically designed for mail services. It provides complete high-availability services and two-way mail replication. No additional hardware load balancers and independent SAN storage devices are required. It also eliminates the limitation of the physical heartbeat connection. With merely two servers, you can construct a high-availability cluster system that is 100% controlled within the enterprise through a simple setup process to achieve uninterrupted services and complete data synchronization. SHA's protection focuses more on file-protocol services, such as SMB, iSCSI, Fibre Channel, and more.

In this white paper, we will introduce the architecture of MailPlus High Availability. We will cover topics such as the load balancing mechanism of core services, automatic failover, and recovery mechanism. We will also explain how MailPlus high availability avoids data loss caused by a split-brain.

We will be comparing this with our Synology High Availability package and explain why the MailPlus High Availability architecture is a more suitable choice for building a high-availability mail system.