一、Red Hat Enterprise Linux
Red Hat's products, there are Red Hat Linux (such as Redhat8,9) and for enterprise version released Red Hat Enterprise Linux, can be obtained free of charge through the network and use FTP, but when in 2003, Red Hat Linux stop the release, it is replaced by the Fedora project project this project, and issued in the name Fedora Core and available to the general users free of charge. Fedora Core Linux distribution update soon, about half a year there is a new release. The current version is Fedora Core 6, Fedora Core test this relatively strong flavor, each issue has a new feature is added to it to obtain successful results will be used in RHEL release channel. Although such frequent updates instability improved products for businesses, not the best choice, most companies will choose paid RHEL products (and there are deep meaning, for example, companies using Linux to make money, earn to return the money to the enterprise, inter-enterprise funds flow back to society, improve service levels, etc.).
In most of the packages constituting RHEL are released under the GPL agreement, that is, we often say that open-source software. Because it is so, Red Hat company also follow this agreement will constitute a package of RHEL public release, then develop and publish as long as the foundation is under the GPL, anyone can constitute in the original software. CentOS is a Linux distribution on the basis of such posted RHEL RHEL clone constitutes reproduction. RHEL clone CentOS not the only one there is White Box Enterprise Linux and TAO Linux and Scientific Linux (others heard of these, is not it?).
Two, CentOS
CentOS is short for Community Enterprise Operating System, we have a lot of people call it a community enterprise operating system, no matter how you call it, it is a Linux release version of the operating system. CentOS is not a new Linux distribution, Red Hat if it comes to this name, everyone seems to have heard of. There are products in the Enterprise Edition of Red Hat family, it is the Red Hat Enterprise Linux (hereinafter referred to as RHEL), CentOS version of this is the clone of RHEL. RHEL is a lot of enterprises to adopt Linux distribution, you need to pay before you can use Red Hat, and get paid the cost of service and technical support and version upgrades. RHEL CentOS can be like the same building Linux system environment, but do not need to pay any costs of products and services to Red Hat, but also do not get any paid technical support and upgrades. Although it is RHEL clone, but not exactly the same, it said cloning is a 100% interchangeability (Really?). But it does not guarantee the corresponding RHEL software can be 100 percent above normal working CentOS. And correction of security vulnerabilities and upgrade packages corresponding RHEL paid services and technical support, it delays a few weeks a few months a few days there (in fact, did not see how slow).
Three, CentOS features
The full name of which we can see CentOS Enterprise OS, that is enterprise systems, this system is not enterprise-level business systems, but it can provide the elements needed for enterprise applications.
E.g:
- Stable environment
- Updated long-term upgrade support
- Strong conservative
- Large-scale system can also play a very good performance
CentOS meet the above elements, as well as to meet the release of Fedora above elements. Fedora and CentOS are very similar, but it is for CentOS, Fedora provides more new features and software, release updates fast and so, so in terms of increased stability and manage a lot of work. Companies need systems environment should be a system of environmental efficient and stable system environment, after a build long-term use, so Fedora release frequent updates as the system environment does not correspond to enterprise applications. On the other hand, CentOS was able to meet the needs of more enterprises in a number of clone version of RHEL, CentOS is a very outstanding very good.
Four difference, CentOS and RHEL's
In fact, why CentOS? CentOS and RHEL What is the relationship? RHEL when issued, there are two ways. One is a binary distribution methods, another way is to release the source code. No matter what kind of distribution methods, you can get free (such as downloading from the Internet), and released again. But if you use their online upgrade (including patches) or consulting services, they had to pay. RHEL distribution methods has been to provide the source code, CentOS is RHEL release the source code to recompile once, forming a binary version available. Since the LINUX source code is GNU, so from the get RHEL source code to be compiled into a new binary, are legitimate. Just REDHAT is a trademark, it must be removed REDHAT trademarks in the new release in. REDHAT attitude of this release are: "We are not really opposed to this release, true to our paying customers, they pay attention to is not the system itself, but the business services we provide." So, CentOS can RHEL get all the features and even better software. But CentOS does not provide commercial support to users, of course, assumes any liability business.
I will gradually go on my RHEL CentOS, RHEL because I do not want to pay for upgrades. Of course, this is because I have years of experience with UNIX, therefore RHEL commercial technical support is not important to me. But if you are a pure business enterprise, then I suggest you purchase RHEL software and purchase the corresponding service. This saves your IT management costs, and get professional services. In short, the choice of CentOS or RHEL, depending on whether your company has the appropriate technology. CentOS (Community ENTerprise Operating System) is one of the Linux distributions, it is the Red Hat Enterprise Linux recompiled from source code (mainly to remove Red Hat trademarks). Why Red Hat CentOS tolerate this kind of behavior? From Red Hat CentOS server to download the source code, compile, distributed free of charge, does not offer paid commercial support. Red Hat released upgrade patch, after a few hours or at most a few days, CentOS patch release will follow. CentOS is perfectly legal to do so, Red Hat had no alternative but its business is based on the open source model. But indeed continue to devour CentOS Red Hat's market, it can be observed from the Google Trends to. From the current situation, the damage caused by CentOS has not yet reached the point where change had to let Red Hat business model. The benefit is that it forces the Red Hat accelerate innovation, so that is always ahead of other Linux server distributions. The real victims CentOS huge success that other distributions, such as Novell's SLES, Ubuntu server.
Supplementary:
1, CentOS also amended some of the BUG AS, such as package installation process of selection
2, CentOS yum online upgrade adds
3,
CentOS-3.1 = AS3-update1
CentOS-3.2 = AS3-update2
CentOS-3.3 = AS3-update3
CentOS-3.4 = AS3-update4
CentOS-3.5 = AS3-update5
CentOS-4.0 = AS4
CentOS-4.1 = AS4-update1
4, CentOS perfectly legal, do not involve copyright issues
5, CentOS is easy to obtain, provide more than 10 sites worldwide mirror (HTTP / ftp), and BT mode (perennial seed).