[Beowulf] Re: HVAC and room cooling...

[Eckhoff.Peter at epamail.epa.gov]

We have 3 - 16 hard drive file servers, 13 compute nodes and a master
unit.  We
had to spread the load from 3 to 4 - 20 Amp circuits to keep from
popping
circuit breakers.

We have AC coming into an interior room and experienced several
problems.

Problem 1:  There was no adequate exhaust system.  5 active vents in , 1
passive
    vent out and in the wrong location.

Solution:  We substituted in several grates in place of acoustic tiles.
     The heat is vented up into the plenum above.  There are fans atop
the rack
    venting the interior of the rack into one of the grates above.  The
other heat follows.

Problem 2:  What do you do when the AC stops?  Maintenance and the
    occasional AC system oops can be devastating to a cluster in a small
room.

Solution 2a:  We are tied directly into a security system.  When a
sensor in the room
   reaches a temperature level, "Security" responds dependent upon the
level
   detected.

Solution 2b:  We installed a backup automated telephone dialer.  Not
that we don't
   trust "Security", but we wanted a backup to let us know what was
going on.
   When the temperature reaches a certain level, the phone dials us with
an
   automated message:
   " This is the Sensaphone 1108.  The time is 1:36 AM and ...
   [ ed.  your CPUs are about to fry... Have a nice night!!!"  ;-)  ]

Solution 2c:  Install a thermal sensor into a serial or tcp/ip socket.
Some vendors
   have software that read these sensors and will shut down the
machines.  We are
   still working on our system.  Others' experiences and solutions are
welcomed.
   We are using dual Tyan motherboards with dual AMD MP processors.

Good luck!!

Peter

*******************************************
Peter Eckhoff
Environmental Scientist
U.S. Environmental Protection Agency
4930 Page Road, D243-01
Research Triangle Park, NC 27709

Tel: (919) 541-5385
Fax: (919) 541-0044
E-mail: eckhoff.peter at epa.gov
Website:  www.epa.gov/scram001

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