On 07/04/11 11:44 PM, Emmanuel Noobadmin wrote: > Otherwise, the single large UPS becomes the single point of failure. the good big ones are fully redundant and every component is hot swappable. but yeah, distributed UPS the way google did it is rather sweet. As long as part of their operating plan is replacing every server by the time its batteries need replacing, they are good to go. You also need the sort of cloud management environment where your servers themselves are interchangable worker units and can be easily taken down for maintenance OTOH, populating lots of racks with several APC SU3000's each is a pain in the butt. Servicing dozens or 100s of per-rack UPS's when they are 3-4 years old and need battery replacement is also very time consuming. a battery tray swap of a decent sized datacenter UPS takes a half day with a small fork lift. -- john r pierce N 37, W 122 santa cruz ca mid-left coast