Re: Machine available for community use

On Mon, 30 Jul 2007, Devrim GNDZ wrote:

> I have performed a test using OSDL test suite a few months ago on a
> system that has:
> * 8 x86_64 CPUs @ 3200.263...
> and RHEL [4.3] performed much better than CentOS [4.3]

RHEL 4 update 3 included some reworking of the x86_64 kernel, like adding
the kernel-largesmp for many CPU systems. I would not be surprised to
find that the first CentOS release based on that may not have achieved a
perfect rebuild because of all that, and since you didn't do any updates
from the initial ISO images you were basically running the CentOS beta for
that feature set.

I think it's accurate to say "sometimes CentOS releases have bugs that
make them perform worse than the RHEL they're derived from", and would not
dispute your results accordingly. I've seen fuzzy periods where CentOS
had a release out to match a new RHEL version, but it wasn't quite right
until after CentOS released an update or two. There can be some lag
there, particularly in the period after a new major release. Right now,
for example, I still don't completely trust the CentOS build based on the
recent RHEL 5, and have been following the developer mailing lists to get
a feel for when things have settled down. It is one of the risks that
goes along with using CentOS, and removing it by using a genuine RHEL
certainly has value.

At the same time, I've done a fair amount of benchmarking work on machines
that switched from RHEL<->CentOS where performance was completely
identical. I'd need to see a lot more than one test result suggesting
otherwise before I'd believe that CentOS is slower in general than the
RHEL it's derived from.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD