On Mon, Sep 10, 2007 at 12:54:37AM -0400, Tom Lane wrote: > Greg Smith <gsmith@xxxxxxxxxxxxx> writes: > > On Sat, 8 Sep 2007, Joshua D. Drake wrote: > >> You would have to have lightning handed by God to your server to have a > >> total power failure without proper shutdown in the above scenario. > > > Do you live somewhere without thunderstorms? This is a regular event in > > this part of the world during the summer. It happened to me once this > > year and once last; lost count for previous ones. In both of the recent > > cases it's believed the servers were burned from the Ethernet side because > > somewhere in the network was a poor switch that wasn't isolated well > > enough from the grid when the building was hit. Lightning is tricky that > > way; cable TV and satellite wiring are also weak links that way. > > Yeah. I've lost half a dozen modems of varying generations, a server > motherboard, a TiVo, a couple of VCRs, and miscellaneous other equipment > from strikes near my house --- none closer than a couple blocks away. > I don't really care to think about what would still work after a direct > hit, despite the whole-house surge suppressor at the meter and the local > suppressor on each circuit and the allegedly surge-proof UPSes powering > all the valuable stuff. I've also moved heavily into wireless local <dons EE hat> Pretty much every surge supressor out there is a POS... 99.9% of them just wire a varistor across the line; like a $0.02 part is going to stop a 10,00+ amp discharge. The only use I have for those things is if they come with an equipment guarantee, though I have to wonder how much those are still honored, since as you mention it's very easy for equipment to be fried via other means (ethernet, monitor, etc). > net to eliminate any direct electrical connections between machines that > are not on the same power circuit (the aforesaid burned motherboard > taught me that particular lesson). And yet I still fear every time a > thunderstorm passes over. Wired is safe as long as everything's on the same circuit. My house is wired for ethernet with a single switch running what's going to every room, but in each room I have a second switch on the same power as whatever's in that room; so if there is a strike it's far more likely that I'll lose switches and not hardware. > Then of course there are the *other* risks, such as the place burning to > the ground, or getting drowned by a break in the city reservoir that's > a couple hundred yards up the hill (but at least I needn't worry about Invest in sponges. Lots of them. :) -- Decibel!, aka Jim Nasby decibel@xxxxxxxxxxx EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
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