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On Fri, 25 Dec 2009, james kilty wrote:
Hello all I asked my son for a comment as this is one of his specialty areas. Here is his reply.
Thank your son for his insight, but I'm happy with what I have and how I'm running my home conputer network.
" Can't think of one offhand but he might find the UPS he has provides some excellent monitoring features via its network card. The larger models (depending on vintage) have a temperature sensor input on the NW card and I think an auxiliary switch input (could be wrong about that - true of APC family which are now from the same parent company, I have recently fitted a stack of these 2 to 5kVA range). In which case a Hochiki 12V smoke or heat detector could be hooked up to it. Or a mains powered one with an optional relay base (available from electrical factors such as City Electrical, WF, Newey etc) would give a volt-free contact output. That output from either type could be connected to the aux input if it has one, or find a way to get an alarm input to the server via a USB or serial or parallel port switch input converter.
I'm not really sure what he thinks I have at home - certianly not a 5KVA UPS ... I've already detailed exactly that I have in there (although I did forget to add 2 DECT base stations and the central heating controller at the time)
It's an older MGE Pulsar 1500C UPS FWIW. It has rs232 output as well as USB... It does provide some monitoring but not a lot (it's quite old itself), and in any case, as I mentioned earlier, it was the monitoring server that croaked.
The cupboard itself is big enough for me to sit inside with the desk, screen and keyboard... So I'm not exactly cramming everything in. Cooling really isn't an issue.
I think what he has discovered is the very urgent need for cooling of computer equipment.
I also think he has somehow gotten hold of the wrong end of the stick. I have plenty of graphs and monitoring systems that tell me exactly how hot it gets and the system certinaly did not fail due to overheating. It failled because the PSU is crap. It's not the first PSU of that batch of 6 boxes I bought 6 years ago that's failled. That's why I had a spare PSU on-hand, although this is the first one that actually made a smell and got hot to the touch when it failled. Most of the others were outdoors (well, in barns or outhouses on farms, so maybe it went unnoticed)
The power density when any amount of kit is packed together - on shelves or a rack - then located in a small space - under the stairs - is much higher than free-air circulation can hope to cool and temperatures of 50C among the gubbins are not uncommon. Enough to kill a hard disk, age capacitors etc. The surface temperatures of any switch mode power supply can be far higher than this.
While I'm sure that's mostly true, it's not relevant to my situation.FWIW: I once ran one of these same boxes inside a sealed case at the top of the lift-shaft in the Cambourne school of art for over 2 years without any issues. Both disk drives ran at 50C and the processor was a little higher. The case also housed 2 Apperto 5.8GHz radio units which only added to the heat. It was still running well when I pulled the plug on all the networking, so could no-longer reach it, and I've never bothered to go back there to collect it, so it's still there and turned on for all I know... (although it has old Maxtor drives which were prone to failure, even when kepy cool)
And maybe you can point your son at the Google statistics published relatively recently, regarding disk drive temperatures and failure rates... (They like to run them hot)
And right now, the disk drives in this server are at:
# hddtemp /dev/sd{a,b}
/dev/sda: WDC WD10EACS-00ZJB0: 30 C
/dev/sdb: WDC WD10EACS-00ZJB0: 35 C
and the motherboard (which only has one temp sensor) is:
# sensors
acpitz-virtual-0
Adapter: Virtual device
temp1: +32.0 C (crit = +100.0 C)
Which I think you'll agree is fine. (And the door has been closed for a
few days)
Cheers, Gordon -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html