Hi Karl, Karl Katzke wrote: > > Actually, I believe that the different vendor implementations of "lights > out" systems (DRAC, HP/Compaq ILO, various others) *do* support that in > various ways and fashions. Dell's RAC has a battery that lasts for up to 30 > minutes last time I read it's specs. Regardless, with a "lights out" card > watching the server, you have two paths to positively query the status of a > node at the node itself, which is enough to be 90% sure it's dead.
if the RAC is on battery, then you could be 100% sure. > The switched PDU devices in question, generally made by APC, have some > instabilities and, well, 'difficulties' in their implementations that are > not well-documented or intuitive. Some models don't inter-operate well with > other models in a mixed environment. And there's no positive feedback from > the node itself; you still don't know if the server's dead or just but you receive the feedback from the PDU itself, which is reliable. > unreachable due to a NIC failure. Checking that the ports you THINK the no, no, if you switch off the appropriate outlets, then you are 100% sure the node is down. > power is on isn't bad, but if the PDU is dead or your well-meaning coworker > changed the placement of the plugs, well... I would say you have a double failure here. > A decent design with DRAC is to have two switches. With the nodes that are > on Switch A, put the DRAC interfaces on Switch B, and vice versa. Switch A > and B should have separate battery backups; APC does make 'dumb' hot-fail > power switches that work reliably. I'm not sure what devices you are referring to here. Are these UPSs? Regards, Peter _______________________________________________ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
