[c-nsp] Multiple power supply failures. Advise needed

[Michael Ulitskiy]

You made me doubt myself and I went ahead and checked the air flow direction in a 
couple of servers I have in the office handy.
I was under impression that all servers power supplies are sucking air, but I was wrong.
Apparently we have servers working both ways. And here I find another clue.
All server PSUs that failed were sucking air. Does it mean that I'm now to expect system 
board problems in those servers with PSUs sucking air from inside the chassis? Oh, come on...
Also I'm not sure about air flow direction in cisco power supplies. I'll check it out on my
next visit to colo.

Michael

On Wednesday 02 September 2009 11:49:59 am Randy McAnally wrote:
> You mentioned a couple servers failed -- most if not all servers power
> supplies blow outward, sucking air from inside the chassis.  Many Cisco
> devices work this way also.  I have rarely seen a power supply that sucks air
> in directly from the outside of the chassis.
> 
> Given the above, much of the dust would settle on the system board.  The
> extremely high tolerances of a typical system board far outweigh those of a
> power supply, thus I would expect system instability before the power supply
> failed.
> 
> My bet is still on power spikes/dips.
> 
> --
> Randy
> www.FastServ.com
> 
> ---------- Original Message -----------
> From: Michael Ulitskiy <mulitskiy at acedsl.com>
> To: "Randy McAnally" <rsm at fast-serv.com>
> Cc: cisco-nsp at puck.nether.net
> Sent: Wed, 2 Sep 2009 11:08:24 -0400
> Subject: Re: [c-nsp] Multiple power supply failures. Advise needed
> 
> > What about the fact that most (if not all) power supplies have 
> > independent sucking fan and that power supply air flow is separate 
> > from the system board flow.
> > 
> > Plus all system board I saw are covered with some insulating 
> > coating. I've never pulled apart a modern power supply. I'd expect 
> > them to have something like that too, but who knows? Plus since PSU 
> > is the only part that's dealing with high voltages I expect it to be 
> > more sensitive to momentary shorts. Am I wrong?
> > 
> > I'm expecting report for provider ordered unintrusive power 
> > monitoring. I'm almost positive they won't find anything, though. 
> > I'm still looking for advice on independent power analysis source in 
> > New York, NY if anyone has this kind of experience. Thanks,
> > 
> > Michael
> > 
> > On Wednesday 02 September 2009 10:29:07 am Randy McAnally wrote:
> > > Plain old dust wouldn't be so picky...it has to be ingested past the system
> > > board before it hits the power supply in most cases.  System boards are WAY
> > > more sensitive to this kind of thing.
> > > 
> > > The fact you have ONLY PSU's failing still makes me think you have power
> issues.
> > > 
> > > --
> > > Randy
> > > www.FastServ.com
> > > 
> > > ---------- Original Message -----------
> > > From: Michael Ulitskiy <mulitskiy at acedsl.com>
> > > To: "Randy McAnally" <rsm at fast-serv.com>
> > > Cc: "Scott Granados" <gsgranados at comcast.net>, "Seth Mattinen"
> > > <sethm at rollernet.us>, cisco-nsp at puck.nether.net
> > > Sent: Tue, 1 Sep 2009 23:21:23 -0400
> > > Subject: Re: [c-nsp] Multiple power supply failures. Advise needed
> > > 
> > > > This is my main suspect now. They are doing work in the facility. 
> > > > Not heavy construction, but they do install cages and cabinets for 
> > > > new tenants and they're definitely using tools that  produce metal dust.
> > > > My theory is that because of we've been the 1st customer who moved 
> > > > into that facility we've been collecting that metal dust for longest 
> > > > and so we're having a lot of problems with our equipment. To my 
> > > > knowledge none of our neighbors are having the same problem, but 
> > > > none of them have been in the place long enough. So the question 
> > > > remains: is there any way to fight it/protect from it except from 
> > > > going through the huge-huge-huge headache of undertaking another move?
> > > > 
> > > > Michael
> > > > 
> > > > On Tuesday 01 September 2009 08:48:38 pm Randy McAnally wrote:
> > > > > He mentioned he was one of the first customers in the colo so
> > > > > this might be a possibility
> > > > > 
> > > > > --
> > > > > Randy
> > > > > 
> > > > > ---------- Original Message -----------
> > > > > From: "Scott Granados" <gsgranados at comcast.net>
> > > > > To: "Seth Mattinen" <sethm at rollernet.us>, "Michael Ulitskiy"
> > > > > <mulitskiy at acedsl.com>
> > > > > Cc: cisco-nsp at puck.nether.net
> > > > > Sent: Tue, 1 Sep 2009 17:35:34 -0700
> > > > > Subject: Re: [c-nsp] Multiple power supply failures. Advise needed
> > > > > 
> > > > > > Also make sure that the provider isn't doing work in the facility. 
> > > > > >  I'll never forget going to an L3 datacenter and arriving to find 
> > > > > > workmen in the overhead grinding away and dropping dust and who 
> > > > > > knows what else in to all the racks below including a rack of Netra 
> > > > > > T1's that promptly sucked in the dust and kicked out power 
> > > > > > supplies.;)  It was definitely metal shavings because they were 
> > > > > > using a grinding type tool up in  the over head frames.
> > > > > > 
> > > > > 
> > > > >
> > > ------- End of Original Message -------
> > > 
> > >
> ------- End of Original Message -------
> 
>