With my ever-growing experience with these things, I'm tending to think that application-level HA solutions are a much more robust way of dealing with the potential failure modes of hardware or software. While this doesn't mean you shouldn't buy reasonably robust hardware (not the cheapest thing that falls off the truck), what it does is mean is that you should probably spend that extra money you would have spent on that redundant storage system and hot-plug-gable whatsit with replicating your server environment and allowing application-level replication such as Cyrus offers to do the rest. This does mean that we need to lean on software "vendors", be it people we pay or ourselves to create applications that provide for application-layer high availability. However, in the long run it IS a much more robust solution, and covers a much larger number of failure domains for the time and money spent than throwing money and effort at covering the handful of failure-domains that comprise a hardware system -- since that really is an infinite money pit. These "quality" enterprise software solutions that we're sold today that rely on "fault tolerant" hardware, instead of being "fault tolerant" themselves are not acceptable. -rob ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html
