Storage itself is handled via the ZFS file system allowing for the ability build out additional storage as and when demand requires. Additional storage can be added live without the need to suspend overall system services.
Every disk on the storage system is mirrored in the event of disk failure. This 'JBOD' approach to storage managed via two separate head nodes, deployed in an automated failover configuration in the event should a single controller fail.
All areas of the email platform are load balanced by the robust Haproxy system. Haproxy works twofold:
We load balance every aspect of our setup, from the servers that process inbound mail connections through to caldav services and the Galera databases that store user account settings.
We are keen supporters of open source at 34SP.com and use the best tools to deliver a world class email experience. These include:
Used to power incoming mail server connects. Postfix accepts email from the outside world.
One of a trio of anti spam tools. Amavisd runs simple tests against all inbound email, triggering further checks to Clamav (antivirus, see below).
More checks are performed by this industry leading spam prevention software. SpamAssassin allows each user on the email platform to personally 'train' the spam systems sensitive there own mailboxes (bayesian filtering) and have user selectable sensitivity to spam.
Policyd 2 (cluebringer)
The final tool in our anti spam toolkit is the brains behind greylisting, a method of challenging mail servers before blanket accepting inbound email. More info on greylisting can be found here.
ClamAV is an open source antivirus engine designed for detecting trojans, viruses, malware and other malicious threats. It is the de facto standard for mail gateway scanning.
This software is used to power our webmail client for a fast and responsive browser based email experience. Roundcube is recognised as a thoroughly user friendly webmail client with a has a modern design. The system has user controllable themes, allowing for improved experiences via smartphones and tablets.