SmarterMail is currently used by tens of millions of users in over 110 different countries. Because SmarterMail is available on Linux and Windows, and is one of the most fully functional mail servers on the market, it often appeals to businesses of all types and sizes. From small businesses to enterprises, hosting companies and ISPs to Fortune 500 companies, SmarterMail allows administrators and users alike to enjoy the reliability, stability, simplicity, and security SmarterMail has to offer.
And now, these same businesses will have the ability to set up a SmarterMail cluster as we introduce SmarterMail High Availability, or “SmarterMail HA” for short. SmarterMail HA offers a fault-tolerant cluster built on the exact same code base as previous versions of SmarterMail and drastically changes the game related to performance, scalability, and uptime.
Benefits of SmarterMail HA
SmarterMail HA extends all the features and functionality of SmarterMail while allowing for an unlimited number of users and domains across a cluster (consisting of hubs, nodes, and centralized storage), making your mail services completely fault-tolerant.
If a business wants to host a million domains, SmarterMail can help achieve that goal. If a business wants to offer millions of free email accounts using a single domain, SmarterMail allows for splitting that domain and its users across the entire cluster. If a business wants to offer a ton of domains and/or a combination of large single domains and lower-tier mail services along with premium mail services across these domains and users, SmarterMail HA can help you do that as well.
The point is, a business can have multiple hubs and nodes, a single hub and multiple nodes, or even one hub with one node. The architecture is purely based around need. The beauty of it, however, is that there is no set requirement: a SmarterMail HA cluster can expand or contract as needed.
Architecture of SmarterMail HA
Speaking of "hubs", "nodes" and "centralized storage", perhaps some explanation of the components that make up SmarterMail HA is in order.
SmarterMail Nodes are very similar to the standard SmarterMail installations that customers and administrators are familiar with today. SmarterMail Hubs are servers that proxy all authentication and content to and from SmarterMail Nodes. The Hubs are responsible for knowing where everything is on the cluster, and it's where administrators can view the status of all Nodes, and Node health. Hubs are also responsible for bringing standby Nodes online to self-heal the customer and continue providing mail services to users.
Then there's Centralized Storage. This is a crucial component for a SmarterMail cluster. SmarterMail offers a number of ways to efficiently use both slower and more performant storage so that you can cost-effectively build your SmarterMail cluster. It allows both Hubs and Nodes to have access to consistent and synchronized data, and provides a critical layer of data integrity and redundancy to the cluster.
Deployment and Flexibility
Flexibility was a key component we worked towards when planning and eventually programming SmarterMail HA. Administrators can start with a 1 Hub / 1 Node roll out, and then start adding Hubs and Nodes, add incoming/outgoing gateways, offload spam and virus checks, drop load balancers in front of the Hubs, have standby Hubs and Nodes ready as needed, and more. It’s truly built with flexibility in mind — administrators can basically build out their deployments as they see fit, then allow them to grow to fit the needs of their business.
Pricing
Even though SmarterMail offers more features than most of the leading mail servers on the market, it costs far less than all of its competitors. Even with that, building a huge cluster could be expensive (hardware and software), so SmarterTools offers SmarterMail HA as a monthly cost to its partners, and the monthly cost is based on usage during that month. This allows customers to build clusters dynamically as their business grows and their needs change. Hubs and Nodes can expand and contract, and the cost of SmarterMail HA adjusts in the same way.
Rollout and Availability
SmarterMail HA has been slowly included in SmarterMail releases throughout 2025. We will be releasing pricing details and partnership information along with the SmarterMail Hub around mid-June. We are currently working with many companies (BETA’s and Production) prior to this release, and if you would like additional information and/or would like help planning your environments or migrations, please contact our support team and we will be happy to help.
If you're interested, we have a downloadable PDF that demonstrates the potential architecture of SmarterMail HA. It's a more complex architecture that includes incoming and outgoing gateways, remote antivirus and antispam, a demonstration of standby Nodes, and more. That said, this is just one example of how SmarterMail HA can run.