[CentOS] Re: dell-lnx-pe] Re: RHEL4 vs CentOS-4

Sat Jul 8 06:40:20 UTC 2006
R P Herrold <herrold at owlriver.com>

[newly cross-posted into the centos mailing list]

On Thu, 6 Jul 2006, Stephen John Smoogen wrote:

>>  I understand that the following products [RHEL v the 
>> CentOS rebuilds] differ in price based on the extend of 
>> support. Apart from that, is there any other difference 
>> (i.e. performance, kernel stability etc)?

CentOS is an outgrowth of early efforts of Lance Davis in the 
UK, and has been consciously shaped, structured and recruited 
by me and a couple of other admins at the end of the RHL 
series to tap 'the best and the brightest' of the pool of 
non-Red Hat RPM based distribution developers to build a 
professonal grade 'community' RPM based successor to RHL; 
some of us ran the cAos-1 high performance cluster oriented 
distribution creation to explore some packaging and 
buildsystem issues, and to build community, tools, and 

Once CentOS was viable, it spun off from being a cAos 
sub-project into the free-standing project it is now; in 
Enterprise Linux community rebuild space, it has essentially 
displaced WhiteBox (in part due to the loss of momentum which 
last years hurricane inflicted on New Orleans, and John 
Morris' fine effort), had a friendly merger in of David 
Parsley's Tao, and regularly has binary updates in place and 
more available than the upstream, due to a massive mirror 
pool, and a smart, geo-location aware update mirror 
dispatching system.

> I don't think this is really on-topic for the Dell Poweredge list.

dunno -- one is commercial and carries front end SLA's, a 
certification program, etc, some non-freely available source 
software, and costs; the other is community, organic and 
consciously without SLA's and the rest, and is not. Each runs 
just fine on Dell hardware (which I have been using on Dell 
PowerEdge kit for many, many years, in specing and delivering 
complex networks to customers) [btw, Matt, et al., thanks for 
the XPS series -- it makes a stable, sweet and scaldingly fast 
Linux lovin' desktop]

> The differences between CentOS and RHEL are mainly in the 
> type and level of support you get from each. CentOS support 
> is whatever you get from IRC, mailing lists or what you 
> will pay a consultant to answer.

The main CentOS IRC channel #centos on irc.freenode.net 
consciously tries to mix relentlessly On Topic, fast, 
technically accurate, work safe _teaching_ replies [based 
loosely on a Socratic method], with a bit of 'floorshow' -- I 
am one of the 'ringmasters' most weekday US business hours, 
and we have developed a cadre of 'regulars,' each of whom 
demonstrates advanced RHCE level expertise in addressing 
questions in real time from all comers.

> The mailing lists and IRC will not spoon feed an answer and 
> will tell a person that they are an idiot directly versus 
> telling their bartender at the end of the shift.

(smile) part of the floorshow design [the channel op's try to 
make the channel the one tab in the audience' IRC client left 
open and on top, so that less skilled admins will 'idle and 
"read the mail"' in it, to see what happens next, and also 
soak up both good BOFH skills and accurate RHCE type training 
;) ]; a careful observer will note that Off Topic participants 
are pointed to other more appropriate venues for their 
inquiries, and cautioned several times before any 
'festivities' occur. [I cc the centos list, as a way to 
publicly thank those participants]

> For as much as I can tell, the base Centos is RHEL 
> recompiled with the same options etc. and the Red Hat 
> trademarks removed. If your organization does not need any 
> support then CentOS can be a good match.

CentOS are very cautious to be 'very correct' as to respecting 
intellectual property rights in the rebuild.

It is also correct that we expressly strive to match build 
environments, and use 'ldd' and other tools to verify as close 
as possible binary compatability to the upstream's binary 
offerings as we can [some recent packages have been built with 
non-released compiler variants at the upstream 'PNAELV', and 
so there are minor known divergences from time to time, which 
thus far have not affected performance];  we upstream issues, 
and proposed fixes from the CentOS Bug tracker into Red Hat's 
Bugzilla regularly, and some of the core are well known 
participants in the 'Fedora' project RH runs.

'performance, kernel stability' and the rest should be 
identical - if a deviation is suspected, I hope for and want 
to see a bug filed;  we will track down a substantiated issue 
reported to our bug tracker; we maintain a reporting address, 
and respond to security inquiries confidentially and promptly; 
we have the expected mailing lists, website, wiki, forums, and 
the rest.  Sometimes our art is criticized as not as flashy as 
some other distributions, but the distribution is not looking 
to win style shows ;)

Commercial support is available from several of the core 
CentOS developers' companies, on an a la carte basis.

- Russ Herrold