Ted,

> >The performance gain made sense then, and it makes sense now.
> 
> Does it with sub-5ms response?
[Ron Hawkins] 

Yes. I usually figure out the saving with 0.35 to 1.5ms response time in
SIMPLEX and 0.75 to 3ms response time in DUPLEX with Synchronous remote
copy. Anything else is usually (not always) a queue. If I use 5ms response
time as you suggest then the benefit is even larger.



> >After all, I'm sure you are one of the supporters of the maxim "the best
IO
> is the one you don't do."
> 
> Yes. But.
> 
> >That's something compression can do for you.
> 
> It's too expensive in a write intensive environment.
[Ron Hawkins] 
I'm missing your point, as I didn't mention a write intensive environment.
My first examples is father to son updates which is 50% write at worse, and
the second example is read intensive.  As the second example is not write
intensive, we agree on the benefit and there is no need to debate the second
example further.

I apologize if it wasn't clear that I did not give examples that apply to
any "environment" be it write or read intensive. This is about compressing
specific datasets as an IO reduction strategy. The first example refers to
compressing a loved one: those datasets that define the critical path of an
application's elapsed time. I state this explicitly in the example. If the
application is unimportant, or there is no measurable or tangible benefit in
reducing the elapsed time then it is outside the scope of my example.

Ron

> 
> -
> I'm a SuperHero with neither powers, nor motivation!
> Kimota!

[Ron Hawkins] I always wondered why atomic ended with a K...

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