[Beowulf] What is the right lubricant for computer rack sliding rails?yh

Lux, James P james.p.lux at jpl.nasa.gov
Mon Feb 9 12:40:00 PST 2009

> -----Original Message-----
> From: beowulf-bounces at beowulf.org
> [mailto:beowulf-bounces at beowulf.org] On Behalf Of Robert G. Brown
> Sent: Monday, February 09, 2009 3:15 AM
> To: Mark Hahn
> Cc: Beowulf List
> Subject: Re: [Beowulf] What is the right lubricant for
> computer rack sliding rails?yh
> On Sat, 7 Feb 2009, Mark Hahn wrote:
> >> The tricky thing with the "rack rail" approach (which we
> use a LOT at
> >> JPL) you give is that if the units have cases that are also full
> >> height, you can't stack one unit directly above another,
> so you have to leave a 1U gap.
> >
> > OK, this may gross you all out, but why mount 1U's
> individually at all?
> > I'm a lazy slob, but I have several 1U's stacked on top of
> each other
> > - after all, how often will you really need to get the
> non-top one(s) out?
> > depending on how fancy your servers are, saving the price of a rail
> > kit might even make $ense.  admittedly, I did this on an older
> > cluster, designed-for-cheapness cluster because I couldn't
> be bothered
> > to order and assemble the rails...
> >
> > wait, how about this: consider stacking 1U servers on their side.
> > you'll still be able to pull them out if you want.  would
> the hardware
> > care about the orientation?  muffin fans wouldn't, and
> disks out to be
> > able to handle it.  come to think of it, there's no reason
> to think of
> > this wrt conventional 19" racks.  you could just weld
> together a frame
> > of nice tough angle-iron supports (of whatever length you
> can manage
> > to support the load without sagging embarassingly ;)
> It's really the difference between a HPC cluster and most
> business clusters.  HPC nodes go in, and they don't come out.
>  Unless they break, and if you get high quality nodes,
> breaking is unlikely.
> > think of it this way: by omitting a proper rack and rails,
> you could
> > probably save something like $60/node.  can you think of a
> better way
> > to spend $2400 (per rack)?  admittedly, that's probably
> only a few percent of total cost.
> And don't forget the ten or twenty minutes of human labor
> required to mount the nodes on the rails, one at a time.
> Take rails out of box, out of back.  Pull out bag of screws.
> Ditto the node.  Set node on side.

For truly expedient...

Stack all chassis in rack with no screws. Front panel ears in front of side rails.
Put 6 foot length of angle iron down front of rack in front of all chassis. (or a wood 2x4 of suitable length)
(or two pieces of wood, one on each side, covering the rack ears)
Ratchet strap* around entire rack, about 3 feet from floor. Tighten.
Second ratchet strap around entire rack, about 5 feet from floor. Tighten.


* Duct tape could be used as well.
**  (the rack will almost certainly be bent by this, and not usable for any other scheme, but hey, if you never have to take the things out, who cares)


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