Why do I choose CentOS instead of Debian/Ubuntu?

We are running some of the world's largest Internet operations. Therefore, we pay great attention to reliability and stability and are our top priority. Therefore, we only use Linux to support customers' systems. But which Linux release should we use? The answer is CentOS. Why? As a huge system operator

We are running some of the world's largest Internet operations. Therefore, we pay great attention to reliability and stability and are our top priority. Therefore, we only use Linux to support customers' systems. But which Linux release should we use? The answer is CentOS. Why?

As a huge system operator, for a long time, we need to find a reliable and predictable system among multiple large systems, we need strong support from the world's most powerful software vendors and open-source projects. For the most commonly used systems, we need documents, tools, and global resources.

For this reason, the RedHat/CentOS series release is our choice. They are able to meet all of the above requirements, with relatively few problems and long-term stability, which enables us to provide world-class maintenance for thousands of systems running different configurations, services and applications.

RedHat's Enterprise Linux (RHEL) is a gold standard Enterprise release. It is updated every five years or so and has great advantages in system stability, foresight, and security. Every time a new primary version is released, such. x or the latest 6.x, all versions and codes will remain unchanged. only security issues or major bugs, such as backdoors and ports, will be fixed by releasing a new sub-version.

CentOS is an open-source version corresponding to the RHEL release. it is usually released soon after the release of RedHat. The reason we use CentOS is that the cost of standard support services for the RHEL release is very high, about $800 per server. for many users who have dozens or even hundreds of servers, this is the cost that must be controlled.

There are two potential problems with the RHEL/CentOS system.

First, once the main version is determined, the content will not be changed except for the security issues and serious faults that will be repaired. Although this is good for stability, it is not good for many services. For example, for MySQL and PHP services, they will carry out heavy development and a lot of modifications during the CentOS/RHEL main version release cycle over the past five years. For example, MySQL5.0 is the default version of RHEL/CentOS, But MySQL has been updated to versions 5.1 and 5.5.

Fortunately, this problem was easily solved by the Yum software package manager. Since then, the main software, such as the actual components in RHEL/CentOS, including the kernel and all tools, still comes from the release version, but the additional software, such as Nginx, Apache, PHP, Java, MySQL, and so on from updated software sources such as Fedora; or directly obtain the updated version such as MySQL from the developer. Here, we have our own dedicated installation image to fully handle all these tasks.

Second, CentOS release lags behind RedHat release, including key patches and fixes. This is particularly significant in the release cycle of RHEL6.x. However, based on our experience, this is nothing to worry about, and it will never become a problem for us.

Many people ask why we don't need Debian-based systems, such as Debian or Ubuntu servers. If there is no choice, we will indeed support this suggestion, but based on our experience, these systems are not as stable and reliable as RHEL/CentOS.

We believe that, to some extent, this is caused by their rapid development and less mature tests between versions and combinations. Despite their popularity, the main service providers and projects still prefer RHEL/CentOS systems, because they can provide services to enterprise customers (especially for Oracle and MySQL ). In addition, Debian-based systems have many kernel and stability problems, especially in our cloud computing services.

For us, the only reason for using Debian/Ubuntu is:

"They can provide the necessary special services for a system, especially when some drivers or IO subsystems need a new kernel ". For example, ext4 file system or log changes in the recent kernel; now, all of this is included in RHEL/CentOS6.x.

Of course, most Linux developers use the Ubuntu desktop version. it is understandable that they prefer to use the same system during development and production, you can also use many interesting tools. But in general, we still think that RHEL/CentOS is a better deployment platform, and more than a dozen customers have successfully switched to use CentOS as the production environment without any problems, however, this is still an arduous task.

In general, you will be more happy to see a well-managed CentOS system. We have thousands of servers using the CentOS platform, and only one server crashes on average every year. It is also hard to imagine that it is so rare, so pick an excellent, fast, and reliable platform!