RE: Why is the iSeries so slow

> From: James Rich
> 
> And no one was talking about multi-user performance of the iSeries,
> either.  The discussion was focused on network performance.  So
> comparing multi-user performance of one machine to network performance
> on another doesn't make sense.  Thus to discuss that one machine is
> doing multi-user work requires that you also address the multi-user
> nature of the other, or eliminate its effects on both.

I'm going to try one last time (and I mean it) to address this point.
If you don't get it, then I clearly am unable to present my position
coherently.  Since I'm an author, columnist, teacher and regular speaker
at trade shows, that's a bit of a concern for me, but I'll get past it.

Anyway, my point is this: the iSeries can NEVER run as close to the
metal as a Unix or Wintel machine.  That's because both Unix and Windows
can function as what are in effect single-user operating systems.  When
you have a dedicated Unix box, it is truly dedicated to just those
things you have running.  That's why I use a Linux machine for my mail -
it runs and runs and runs, and doesn't need much in the way of hardware
or software.  Windows machines run similarly.  In fact, while Unix is at
least built for multi-user support, Windows is really a single user
system.

Then there's the iSeries.  Horizontal and vertical microcode separate
the operating system from the metal (thus allowing us the unparalleled
ability to move entire applications from one set of hardware to another
without rewriting a single line of code).  OS/400 is built from the
ground up to be multiprocessing, and not only that, to segregate batch
and interactive processing (although this particular feature was grossly
abused by the folks that set prices).  Given the price of the memory,
the system was designed to be entirely virtual, meaning that there's
more swapping going on in a typical iSeries than on any Windows or Unix
machine.  In fact, I would state that a single-purpose Windows or Unix
box with 1GB of memory should never swap.

Meanwhile, even at rest I'm still getting about 30 page faults a minute
on my iSeries (not to mention some 800 active-wait transitions).  Now,
is that because the iSeries is wasting cycles?  No, it's more like the
iSeries idles a little higher than the family sedan, is all.  So, while
you may not get from 0-60 as fast in the iSeries, it's got a lot higher
top end, and it can run at 120MPH for a long, long time.

Because of that, the ONLY fair comparison between an iSeries and a Unix
and/or Wintel machine is when running at full load - dozens of users,
hundreds of jobs, millions of records, subsecond response time.  Throw
in TCO and especially administrative staff costs and the comparison
becomes realistic.

Comparing the two boxes performing a dedicated task is simply unfair,
because the iSeries sleeps a lot harder.  Now, this is my opinion.  You
may not agree.  You may think it's a perfectly fair comparison to say
that your $800 Dell is a faster DNS server than your $250,000 iSeries.
And that's when I say, yes it is, but it sure can't run an enterprise.

And that's why I also say, to each job the right hardware.  Personally,
I've always advocated tiered architectures, and it's a matter of
security and uptime as to whether the web tier is an iSeries or a Unix
machine.  As I've stated, I run Linux for my mail server; a dedicated
Linux mail server actually probably has a better uptime than an iSeries
(GASP!).  But that's because a dedicated mail server doesn't really do a
lot of hard work, at least in my shop.

Anyway, that's my position.  If you want an $800 iSeries, you're not
going to get it.  So buy a Dell and get on with your life.  Use the
iSeries for what it's meant to be, a powerful, reliable back-end server.
And if you can't sell your customers on the benefits of a tiered
network, then by all means get an MCSE certification.

Joe