[Beowulf] urgent: cost of fire suppression?

[Mark Hahn]

>> I thought halon gas was the usual choice for datacentres, has that gone
>> out of fashion?
>
> It was quite popular. However, it's not friendly to the ozone
> layer... which means it's phased out due to the Montreal Protocol.

I found http://www.firesuppression.co.uk/ quite useful, since it 
let me plug in the room specs and get useful budgetary numbers.

in particular, http://www.firesuppression.co.uk/fire-suppression.aspx
discusses several options, their mechanism and environmental footprint.

> But realistically,the need for ³non-damaging fire suppression² has gone
> away for a lot of data centers, since they have to have good disaster
> response plans with very fast response times compared to the 70s and 80s

for HPC, the situation is quite different from commercial or enterprise.
the value is only there if the cluster is operating, and the total value is 
dominated by the capital cost of the cluster.

sure, valuable data can be stored elsewhere, geo-erasure-coded, etc.
but the data isn't the valuable part, but rather the operating flops.
say, 8M capital cost of computers, maybe .3m/year in power,
and the opportunity cost of a fire is really just how many flops 
we don't get.

hard to say whether spending, say $50k to extinguish fire really makes 
sense.  it would be bad to burn the rest of the building down (big old 
semi-brutalist structure, not sure how likely fire would be to spread.
probably my office would go first.)

as far as I can see, all of our cables are marked just CL2; I don't know
how much this affects the chances of propagation (ie, being non-plenum-rated).
other than cable jackets, just about the only other flammable thing in the
room is the wood-core tiles.

assuming the chillers stopped moving air, I guess fire would have a hard time.

> sharing), you can use water to put the fire out enough to save lives, and
> let insurance haggle about the equipment replacement.

I don't know about other universities, but we're "self-insured" (which means
that there would be no replacement...)

regards, mark hahn.