VFEmail is in the final stages of a set of whirlwind upgrades. In the end, we'll have upgraded hardware, software, and a better overall design.
VFEmail also runs Openmail.cc. These two sites share hardware and core infrastructure, but currently operate mostly independently. Only the user authentication has been merged. Webmail is still a separate database and install, though the same webservers are used. See - www.vfemail.net vs openmail.cc
Over the last 10 years VFEmail has slowly grown from a single PC to multiple systems. We've survived the 'free email' arena by not outspending our competition, we upgrade when it is affordable.
Now just about each service has a dedicated server. We have:
2 SMTP sending servers
3 incoming MX servers
2 Web Servers
2 DNS Servers
2 Spam Servers
2 SQL Servers
1 'Misc' admin server
1 offsite backup NAS
2 Load Balancing routers in master/slave config
Any servers of which there are at least 2, except the load balancers, are Virtual Machines. These are backed up to the primary NAS weekly and replicated to the offsite backup NAS. In the future, we plan to replicate data as it is written to provide even better service.
Each web server points to a VIP internally for SMTP and SQL access. That allows us to provide 100% failover for either service. Incoming Web and SMTP are equally load balanced. At this time POP and IMAP are directly hosted on the NAS to increase response time. The idea being that since the NAS is not 'hot replicated', if there is an issue it will affect POP/IMAP anyways. In the future, POP/IMAP will be extracted and load balanced as the backend data is replicated between two hosts. Other providers do this with DRDB, but VFEmail uses ZFS on the backend, so that's not an option. ZFS does provide for regular snapshots and easy replication, backups, and restores -but not live replication. AVS + ZFS would provide that, but I was never able to get that functional, so I'm keeping a close eye on FileReplication Pro as a possible alternative.
Next up, new User Control Panel, Horde 5.1, and Roundcube upgrades.