Michael Tokarev wrote:
Unfortunately an UPS does not *really* help here. Because unless it has control program which properly shuts system down on the loss of input power, and the battery really has the capacity to power the system while it's shutting down (anyone tested this? With new UPS? and after an year of use, when the battery is not new?), -- unless the UPS actually has the capacity to shutdown system, it will cut the power at an unexpected time, while the disk(s) still has dirty caches...
I'm unsure what you mean here. The Network UPS Tools project http://www.networkupstools.org/ has been supplying software to do this for years. In addition, a number of UPS manufacturers including APC, one of the larger ones, provide Linux management and monitoring software with the UPS. As far as worrying whether a one year old battery has enough capacity to hold up while the system shuts down, there is no reason why you cannot set it to shut the system down gracefully after maybe 30 seconds of power loss if you feel it is necessary. A reputable brand UPS with a correctly sized battery capacity will have no trouble in this scenario unless the battery is faulty, in which case it will probably be picked up during automated load tests. As long as the manufacturers battery replacement schedule is followed, genuine replacement batteries are used and automated regular UPS tests are enabled, the risks of failure are small. Regards, Richard - 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
