On Thu, Oct 20, 2011 at 04:52:57PM -0400, Doug Hughes wrote: > On Thu, Oct 20, 2011 at 3:08 PM, David Bronder <[email protected]>wrote: > > > Luke S. Crawford wrote: > > > > > > I've been mounting switches backwards forever; I mean, the ports are on > > > the back of the servers, right? it only makes sense. Now, normally, > > > I put it at the top of the rack and it works fine; excess heat gets > > > sucked out through the fan at the top of the rack. > > > > > > > Some switch vendors have models now that have the airflow going in the > > opposite direction, suitable for mounting in server racks, or that even > > have reversible airflow so you can choose. Something to look at for > > new switch purchases. > > > > What David said. Force10, Arista, Blade, and others make switches that you > can just get the reverse power and fan modules and you're set. Big win. > (that's what we do) > you're not doing your switch any favors by letting it suck hot air into > itself, regardless of what you end up doing with the exhaust (even though > switches can typically handle higher ambient).
Hm. thanks. yeah, I'll get one that exhausts properly next time I buy switches. For now, like someone else said, if the heat from a switch cooks the server, that server probably needs to be replaced anyhow. I tried to put a 115w socket C32 chip in a 1u with weak cooling (a supermicro sc811) and, well, it passed burn in, but only 'cause I only fail things out of burn in if they crash or if they fail a test like memtest. It got hot - I should fail things out of burn in if the CPU temp gets too high. The co-lo I'm in (14th floor of market post tower in san jose) does something kinda interesting with the cooling; they actually blow cold air down the hot row. I asked my reseller about it, thinking some idiot just mis-labeled the hot row and the cold row, and he said that this was 'optimal airflow' I mean, the place is cold even in the cold row (which is warmer than the hot row) so I'm not complaining too much, but it sure seems wrong to me. (though, it should help some with this particular problem.) I hear that serious datacenters isolate the hot row from the cold row and just exhaust hot row air to outside. I imagine the isolation takes a bit more effort from the people managing the racks than you can expect in a multi-tenant setup, which is why all the co-los I've seen are essentially mixed-air, though they do only spray the cold air down every other row and the servers are stacked accordingly. Meanwhile, I'm going to put this 115w chip in a 2u or 3u chassis with a lot more fans and a much larger heatsink, and I'm going to update my burn-in procedures so that I don't put iffy stuff into production. There's no reason to skimp on cooling fans. _______________________________________________ Tech mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
