RE: Will Upgrading to V4R5 impact performance??? -- MIDRANGE-L

On Wed, 10 Oct 2001, Bale, Dan wrote:

> Doggone you James, I shoulda known someone was going to mention Linux!
> O.K., let's rephrase the question:  Is there *any* enterprise-level
> systems' OS upgrade out there (all vendors) that does *not* take more
> resources to operate than the previous levels?

Well I consider linux enterprise-level.  I guess it depends on what
"enterprise-level" means.  Running on S/390 I think qualifies.

> And James, I'll ask because I truly don't know.  When you first
> installed Linux on that "old hardware", was that system near maxxing
> out?  Or did you have headroom to grow?  Also, specific to the question
> I originally asked, do the newer Linux versions take more or less
> resources than earlier versions?

To answer this question we have to look at what task each machine is
performing (this is true of every time one looks at matching machines to
load as we have seen on this list already regarding as/400 vs. NT
backends, frontends, etc.).  Back when we got the machines they were
loaded with Windows and there duty was as a desktop machine with client
access installed.  Even for these small duties I believe they were near
"maxing out" (though it didn't really matter - it's just a desktop
machine after all).  But with linux installed they are not even close to
their max under similar duties.  The machine I'm currently using used to
be somewhat sluggish performing its duties as a windows desktop.  When I
switched it to linux it sped up considerably.  After upgrading the linux
distribution to a later release it did not slow down.  Several times after
upgrading the linux kernel the machine has *sped up*, not down.  This
includes times when it is maxed out (i.e. swapping heavily, under large
load).  It runs faster on a later release under maxed out conditions than
it did on older releases.  Linux is the only OS I know of that has done
this.

Our results with desktop machines that we have converted to linux servers
are even more satisfactory.

But as I mentioned before, all is not rosy.  Newer releases (of both the
kernel source code and of OS-specific software) take up more disk space
and sometimes more ram than they used to.  Though the linux kernel hasn't
really grown in terms of ram used by very much, the system software has
grown, as has X, mozilla, gnome, kde, tn5250, emacs, windowmaker, gimp,
alsa, etc.  So while I can run the latest kernel on my old laptop I can't
install much of the new software on it.  Not enough disk or ram to run all
the new, cool, and useful stuff.

It could be that OS/400 is the same way, but we aren't able to seperate
components of the system the same way.  Maybe the V5R1 kernel runs faster,
but query or pdm or something takes up more space/ram/resources/whatever.
Windows is largely the same:  you can't have windows without explorer
anymore (or win media player now it seems) so who knows if the "kernel
proper" runs faster or not?  You can't upgrade just what you need - it's
all or nothing.

James Rich
james@eaerich.com