> On the other hand, by the time you're at a thousand rackmount Intel > boxes versus a zSeries capable of hosting 1000 Linux images comfortably > (though certainly not with as much CPU per image as the Intel boxes--so > obviously this is a solution you'd only want to evaluate for I/O, rather > than CPU-bound loads), the hardware cost is more-or-less the same > (within a factor of two, let's say--which sounds weaselly, except for > the next sentence). At that scale, neither hardware nor software is the > major cost of running such an operation: your facilities are. > > One zSeries box plus attached DASD takes up *much, much* less floor > space, power, cooling, and required maintenance personnel than a > thousand Intel boxes.
Rich Fuchs (once of System/370 performance fame) did some work on server consolidation at IBM. He found major issues not just in the number of vendors involved in most organisations, but the number of different and often mutually incompatible levels of each vendor's operating systems. I remember discussing one shop where management though they had around seven different types of 'source' server as potential candidates for consolidation - by the time they'd finished (allowing for incompatibilities within product ranges) they had found over thirty. There are disadvantages in centralising (you have to meet the availability requirements of the most stringent application across most if not all of the configuration) but the control and discipline of a single software environment (IMO) easily compensates. -- Phil Payne The Devil's IT Dictionary - last updated 2002/01/20: http://www.isham-research.com/dd.html UK +44 7785 302803 Germany +49 173 6242039
