Re: What does "scalable" mean?

[Dan Brinegar <vr2link -at- VR2LINK -dot- COM>]

At 9:37 AM -0400 4/27/98, Brian Lightfoot wrote:

>What does it mean when someone says that a server[or database] is scalable
>or not
>scalable?

If the term is being applied in a technical sense, rather than a marketing
sense, "scalable" means one can add hardware or software modules to
increase capacity or capabilities  -- say you're going from 500 users to
5000 users on your intranet server: adding memory to the machine, and
changing settings in the "Users" control panel to allow 5000 simultaneous
connections would mean the thing was "scalable." If, on the other hand, you
had to add ten new *servers* to handle the increase,  in a technical sense
*that* system would *not* be "scalable", although the kids in marketing
might make a claim of scalability anyway...

>.... is "scalable" a legitimate
>technical word or is it just a generic word people can apply to
>anything, (i.e., "my car is scalable" or "my refrigerator is scalable.")

Lessee here, if a car were "scalable" it would have to be readily converted
from the two-seater you bought into a four-door, or a station-wagon, a
strech limo, or a pickup truck -- reaching real hard for an analogy here,
the Model-T has almost-always been readily scalable with 3rd-Party kits,
while a 1989 Dodge Daytona was not -- a '69 Dodge Dart was scalable in that
you could go down to your MoPAR supplier and get  a trailer hitch,
heavy-duty suspension and 383 V-8 & K-member to replace the Slant-Six it
came with, and take the kids and a trailer to Yosemite .

Remember the commercial here in the states where the two sysadmins were
panicking because a ton of "flame mail" made it through to their boss? [The
boss probably said something disparaging about Apple or STC in a public
forum]... one sez "why didn't you stop it?"
"Can't, it's not scalable!" sez the other.

Not scalable in this case *possibly* meant that they either couldn't add
software modules that would filter obvious spam/flame mail or that the
existing setup couldn't handle the large increase in message traffic and
still work properly; so it choked it all down and stopped doing other
things while it processed the email traffic, or it crashed and didn't
filter when they brought it back up -- some readers may be familiar with
getting tons of email they've already gotten, plus tons of spam after their
Internet Provider crashed and came back up...

HTH

-----------------------------------------------------------
Dan BRINEGAR, CCDB Vr2Link
Performance S u p p o r t Svcs.
Phoenix, Arizona

"This is not a Fat Guy confined to a wheelchair...
  it's a new Telecommuter saving tons on auto insurance."