Re: Ambient temperature control

On 7/3/2024 6:05 AM, legg wrote:

On Tue, 2 Jul 2024 08:26:24 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:
 

On 7/2/2024 7:30 AM, legg wrote:

What's the mtbf of a fan? a compressor? a pump?
. . . . or a clamp and a block of aluminum?

>
As long as it isn't significantly worse than the impact of NOT
having it, you don't care -- because some (relatively unskilled)
local contractor can fix those things.  You don't have to
hire a skilled member of staff to be on-hand to deal with the
"more sophisticated" technology's potential failures.
>
I'd much rather have an HVAC guy come in and repair the AHU in
the datacenter -- even if it was an annual event -- than have
to risk servers crashing or having to be replaced (and the
data recovered).  The former is a "cheap", ubiquitous skillset;
the latter considerably costlier and critical.

 
You know what a brass tack is?

>
Exactly that!  You (as an owner of a piece of kit that you RELY on and
have invested considerable time/monies) don't care if it's theoretical
reliability is lowered; what you care about is how *effectively* reliable
that device will be.  How costly (time/money/inconvenience) is it to
KEEP it in service?
>
This is more than just reliability *or* availability.
>
If you had to replace a server because a cooling system outage allowed it
to experience 50C, you'd likely be significantly inconvenienced.
>
If, however, it can continue to operate at 50C -- but with some damage
that will eventually manifest in a reduced lifetime/reliability -- then
you can weather the short term "problem" and plan on taking action
to avoid the anticipated problem -- additional maintenance.
>
If it is the nature of your business to replace items regularly,
then it's likely that your replacement interval has already factor
into it these types of "disturbances".
>
If, OTOH, you don't expect to be replacing (expensive) kit, then
anything that compromises that assumption wants to be avoided.  How
often do you replace major appliances?  HVAC systems?  How inexpensive
(time/money/inconvenience) would the replacement need to be in order
for you to tolerate a shorter lifespan?
>
Or, how much MORE would you be willing to pay to avoid that
replacement?
>
[There are many devices that I would gladly "pay double" for the
ASSURANCE (not some legalistic "warranty" but the genuine
knowledge) that a device *won't* break in a given period of
time.  I.e., the equivalent of having a cold spare on hand -- but
without the space required to store it or the effort required
to put it into operation]
>
If your products have lifespans on the order of a decade or less,
(or, if they are inexpensive to buy/replace) then you likely never
consider these things.
>
[Our KWHr meter will be replaced this week.  Along with every
neighbor's.  This is the only way the expense of such an activity
can be reasonably managed -- sending out a linesman to replace ONE
meter would be extremely costly!  But, having a crew step-and-repeat
down the block is much more manageable.  What added feature would
motivate them to replace them a *second* time while they still
have serviceable life?]