Even though CentOS has officially been a member of the Red Hat family (and sponsored by Red Hat) since January 2014, it is still supposedly an “independent” operation with different enterprise teams. At first glance, though, it would be hard to differentiate the new CentOS 7 from the latest version of Red Hat Enterprise Linux (RHEL) – unless you look at the price tag, of course, since CentOS is free.
Performance
We’ll start by looking at the most important bottom-line factor: performance. Both end-users and independent testers report that with most configurations, Red Hat 7 and CentOS 7 perform virtually identically. For example, tests at ExtremeLabs in Indiana were run on a variety of CentOS versions and a number of different hardware setups, and the performance, compatibility, and footprints of the higher-priced brand and its poorer relative were basically the same: very strong. CentOS 7 is stable, and just about as fast as RHEL 7 – which means that it’s 10-25% faster than its immediate predecessor, Centos 6.5. It’s a very good choice for a Linux platform.
The one major exception comes for configurations which are highly-clustered; Red Hat offers optimizations which aren’t available in CentOS 7. However, since the platforms share almost identical architecture, it’s possible to find workarounds by searching the Red Hat website.
Technical Considerations
There are a number of CentOS 7 versions available and numerous build options can be chosen depending on your needs. And since this isn’t Red Hat there’s no add-on license fee to replicate your builds. An enormous number of add-ons are available for different environments; most will look familiar to Red Hat users. Installation is relatively uneventful for those experienced with previous CentOS or RHEL versions, although some have reported glitches installing to a desktop system.
Now for the technical “issues”, you need to know about CentOS 7. The biggest is that unlike Red Hat, Centos only supports x86_64 64-bit processors. That won’t be a problem for most, but it is something to be aware of.
An important change is the use of a "systemd" daemon as the primary controller in CentOS 7 (as it is in Red Hat 7), rather than the "initd" used in CentOS 6.5. Many Linux enthusiasts believe "systemd" is the work of the devil because it can have a tendency to conflict with other existing daemons, but it’s the “flavor of the year” and it’s going to be tough to escape.
The CentOS 7 default filesystem is XFS and not EXT4, which was the default in 6.5; many believe that EXT4 was the better choice because of speed, but it’s easy to switch back to EXT4 if you prefer. One change for the better is the move from the 2.6.32 kernel to the Linux 3.10 kernel in CentOS 7; that’s a definite improvement for memory management. Finally, version 7 also includes 3D graphics drivers, Open VMware Tools and OpenJDK-7.
Support
Those choosing to go with CentOS 7 over Red Hat 7 will still run into the same issue which earlier CentOS users have experienced: lack of support. CentOS is a free platform, so you won’t get the same relationships or support that you receive when purchasing Red Hat – after all, that support is part of what you’re paying for when you lay out the money for RHEL. And the CentOS website is a far cry from the RHEL site; it’s often tough to find answers there.
The good news is that most of the same answers you’ll find on the Red Hat website will apply to CentOS 7 as well – so as long as you’re an experienced user, a do-it-yourselfer, or someone who’s up for a bit of a challenge, CentOS 7 is a solid Linux platform, and worth much more than what it costs.
