What is Oracle Linux?
On its face, Oracle Linux feels like just another Red Hat Enterprise Linux (RHEL) derivative. It uses anaconda for an installer. It uses yum for handling packages. Configuration is handled just like RHEL, CentOS, or Scientific Linux. To be honest, the reasons why anyone would switch to Oracle Linux aren't immediately apparent after installing. It feels like nearly any other Linux with the Oracle name bolted on. Under the hood, however, are some rather compelling features.
The Unbreakable Enterprise Kernel
I have to start off with saying that I hate the name "Unbreakable Enterprise Kernel." I've seen enough crazy stuff in my time, to know that no software is truly unbreakable. It might be pretty good, but unbreakable is like calling the Titanic unsinkable. Given a poor enough captain, or in this case, an administrator, I don't have any doubts that the kernel could be broken in at least some fashion. However, I suppose that "Unbreakable Enterprise Kernel" sounds a lot better than the "Pretty-dang-tootin'-robust Enterprise Kernel," and with a target like enterprise customers, terms like "Pretty-dang-tootin'" just won't get stuffy execs to authorize using Oracle Linux.
With that off my chest, let's see what the Unbreakable Linux Kernel does have to offer. Oracle has added a number of their own enhancements into a Linux 2.6 kernel. These include networking optimizations, NUMA optimizations, and enhancements for OCFS2, asynchronous I/O, SSD disk access, OLTP, and more. They clearly work pretty well, as back in March, Oracle submitted a TPC-C benchmark for a Sun Fire server that was the fastest x64-based non-clustered system.
Ksplice: Update Your Kernel Without Rebooting
Ksplice was acquired by Oracle roughly a year ago, and as a result is married to Oracle Linux rather nicely. Ksplice is the holy grail for any administrator who is obsessed with uptime. It gives you the ability to update your kernel, with no downtime necessary. This is by far the best reason to use Oracle Linux, but it also comes at a steep price. While support for Ksplice is present in the Unbreakable Enterprise Kernel, it does nothing without the Ksplice Uptrack service enabled.
How does one get Ksplice Uptrack? It's only included with an Oracle premier support contract. While Oracle is quick to note that it costs less than a similar-tier RHEL support contract, it's also still more than most people would want to pay for just reboot-less kernel updates. Sure, there's also actual support included in the contract, but the lack of an ala carte option for just Ksplice Uptrack doesn't make a premier support contract any easier to swallow.
I should note here, that regular package updates via yum, and regular kernel updates via yum, are still totally free. If you don't mind rebooting, Ksplice isn't a must-have. If Oracle wanted to attract more customers, an ala carte option for Ksplice Uptrack would be a step in the right direction. If they wanted to really build some good will with the Linux community, they'd make Ksplice Uptrack free for everyone. I know it may sound weird to mention Oracle and good will together, but I'd never thought I'd see Oracle and "free" mentioned together either. As it is, it feels like Uptrack is being used as the bait for a support contract, when the support contract should really be able to stand on its own.
DTrace: Debugging and Troubleshooting in Real Time
To be fair, the DTrace modules can be plugged into a lot of Linux kernels already out there, but Oracle Linux has done the leg work for their users. Maybe you're not doing the sort of development that requires DTrace, but it's still something handy to have in the toolbox when something breaks. It's also a handy way to profile already running processes at any moment, with little to no impact on performance when tracing a process. Oracle maintains a long list of DTrace resources on their OpenSolaris site.
Should I give this a look?
If you're already perfectly happy with your RHEL or CentOS Linux install, Oracle Linux is a hard sell, even at the price of free. After toying about with the system, I'd say it's at least worth a hard look. As it is, you get the benefits of CentOS or Scientific Linux, with Oracle's own stuff bolted on, and their enhancements, even minus Ksplice, make a compelling argument to use Oracle Linux. If you are setting up a machine to use Oracle's database software, Oracle Linux is the best choice, since it's been designed to support Oracle DB, and is the same Linux that Oracle uses in-house. While Oracle's premier support contract is cheaper than the RHEL alternative, the actual cost of switching from RHEL to Oracle in a given case may not be. While this release is a good first step for Oracle, more options, like free Ksplice Uptrack, or even a Ksplice Uptrack subscription, would make it an easier sell.
If you'd like to give Oracle Linux a try, without having to jump through a lot of hoops, the Oracle Linux Wiki has a list of download sites.