On 7/1/2011 12:36 PM, Timothy Murphy wrote: > Rudi Ahlers wrote: > >>> It seems to me that it should be possible >>> to have a simple, torch-battery operated, system >>> which will keep the machine alive long enough >>> to make a graceful exit. >> A UPS would be your simplest option here since the UPS can send a >> signal to the OS to shutdown properly. >> >> Using a "torch battery" (I presume this is a large torch?) you'll >> still have the same issue as you have now - when the battery runs flat >> (i.e. power outage is longer than 10 minutes or so) Linux will still >> crash uncleanly. > As will be obvious, I know nothing in this area. > My thought was just that the machine only requires say 30 seconds of life > to shutdown properly, and I would have thought > there was enough capacity in a large torch battery to supply this? > > But there seems to be a 100% backing for UPS, > so I'll look into that. A UPS is the implementation of your "torch battery" idea. Remember that the battery will need a way to convert from DC to the A/C power required by your machine. There also needs to be circuitry to switch over to battery power in the event of an outage. You also need to make sure the battery stays charged. The UPS does all of this for you. The UPS can also notify your server in the event of a power outage so it can shut down cleanly. If you don't require a long runtime, then you don't need to get a huge UPS. APC's website has a calculator that can help you determine which UPS will work best based on your equipment and desired runtime. -- Bowie