> The reference server(s), which can also be the HOT READY servers > translate the traffic to the appropriate address and, as far as the > users are concerned, the mail server is ALWAYS up, whether they hit > the server in Chicago, Boston, Arlington Heights, Los Angeles or > Dallas...The data is always kept synchronized between all of the > servers. We have T-3 and OC3 pipes to handle the traffic between all > of the centers on four different backbones. Each center has multiple > power grids and monster battery and diesel power backups and > multiple tons of AC per location.
IOW, a geographically distributed full cluster (geocluster). > after a somewhat simplified and drawn out explanation Which one was it? :) > Has anyone else done this? We have installed geoclusters with IMail, yes, using a number of different technologies. The question is not one of inter-peer bandwidth, really, it's one of disk I/O on each member machine. As you should already know, disk I/O is e-mail's bottleneck; there are numerous threads in the archives covering best practices in this area. If you are aggregating a ton of traffic on a single machine, you can easily max it out--never mind the clustering--so what you need to do first is rightsize one site as if were the sole production environment, then add on resources to account for replication overhead. Your foremost concentration should thus be on getting a single robust, scaleable active pathway for all mail, including offloading to dedicated gateway and utility (anti-virus, anti-spam) servers in addition to the mailbox server. After that, realize that in the event of failure, you may be adding additional deferred-commit stress in precisely the area that is already most taxed, so beef that up with additional spindles, controller cache, and RPM. And, of course, make the inter-peer traffic travel on its own backbone and use intelligent server-grade NICs and high-grade data-link equipment to make sure that network I/O is as trouble-free as possible. In addition to using gateways to reduce stress on your mailbox servers, you should investigate strategies such as IMail's peering and/or address rewriting by *nix MTAs, which can help you minimize replication traffic to/from each single server by distributing users across multiple mailbox servers at each site. -Sandy To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
