All colo facilities are required to have a complete power cut-off switch for fire fighter safety. Its behind the UPS stacks, specifically so that they know the racks aren't energized before they go in. Apparently, the big red button that activates this cutoff is an easy target for people to accidentally lean on or similar, so all power goes down immediately. http://www.google.com/search?q=data+corruption+colocation+power+cut+off+write+caching As an example, the first result there is for wikipedia, which you've probably heard of ;-) LiveJournal (another huge site) was also bit by this. Bottom line is, if you are in a colo, there must be a switch between all power service and your machines, so you are susceptible Posted back to linux-raid for general interest. Maybe everyone else isn't interested, but I'm fascinated by gotchas. I'm sure at least a few others... -Mike Mark Hahn wrote: >>In particular, drives like to enable write-caching out of the box now, >>which opens a window for data corruption that has bitten more than a few >>high-profile sites as it causes the disk to break the fsync contract > > > I'm curious for details on which sites and how they broke. > I can't think of a scenario (except perhaps operating a server > without UPS) were this would be a problem. maybe servers > that are otherwise in such bad shape that they crash? - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
