Oracle Unbreakable Kernel

[Nikky Schreier]

2If you are planning to run Oracle database / MiddleWare / E-Business on Intel/ Linux then select Oracle Linux. Because you get one support portal "Metalink" to manage your support issues for all the software components. In case you run RHEL, you will end up in managing Oracle and RHEL support separately.

3. Oracle Cloud Infrastructure (OCI) runs on Oracle Linux, and Oracle Exadata runs on Oracle Linux. In case you plan to migrate your Oracle workload to Oracle Cloud (OCI) or Exadata in future, the migration will be seamless.

5. Commercially Oracle Linux gives you better price as compared to RHEL. Simply compare Oracle Linux Standard Edition with Ref Hat Linux with 24x7 support and you will understand the difference. This is because Oracle Linux support comes from Oracle Metalink 24x7 by default. Thats not the case with Red Hat

Just the location of the repository for the most part. If you're running Oracle databases on RHEL I recommend purchasing Oracle X-8 hardware and running Oracle Enterprise linux instead, you will save a lot of money in the long run.

The biggest advantages OEL has is that if you buy the Oracle hardware you get support for the OS for free. If you run databases on Oracle hardware your core licensing costs are usually cut in half. Oracle Linux on Oracle hardware also allows for the use of OVM (like vmware) The main disadvantage of the OVM over VMware is that the OVM software is still underdeveloped a little and requires a little more effort for disk functions.

Oracle Linux is developed by Oracle Corp. Oracle ULN (unbreakable Linux (UEK) as they call it, has come into existence since the time Oracle started to invest in Cloud computing. It is again Kernel-based under GNU license. It is now majorly used in Oracle cloud platforms and Oracle Exadata or Oracle Database appliance.

RHEL Linux is developed by Red Hat which also uses Kernel-based under GNU license. RHEL can be used in local desktop, servers and also it can be used on IBM mainframe Hardware (Z13/Z14) as Zlinux and LINUXONE platform as well. They both have similar interfaces (GNOME) except Oracle has KDE as well. Moreover, they use the same terminology and commands to execute on their Linux versions. Oracle Linux uses RPM packages where RHEL Linux using RPM as well as YUM packages and both support containerization and dockerization.

Both Linux distributions are binary compatible with very similar functions and utilities. The same is also CentOS, that is build on the same source codes.

I choose RHEL for:

1. better support (at least for problems that I faced with)

2. quicker security patching

3. additional products that are build on RHEL (RHEV, Middleware products, GlusterFS)

I'm not sure about the performance of Oracle DB on Oracle Linux with comparing to RHEL. I would like to see some independent performance analysis.

We have used both RHEL and OEL for running large Oracle DBs.

If your company only uses Oracle products exclusively then OEL might be an appropriate choice.

If your company has other non-oracle products, then RHEL probably would be an appropriate choice for you.

We are currently running RHEL in the Major Public Clouds as well, and it is supported fully.

Please consider ease of updates as well, as for us yum update with lifecycle management from Satellite works very well and can be based on specific application business needs (e.g. SAP Hana).

Thanks to my colleague Kamil Budinsky from ACS/CSS in Oracle Slovakia who did some tests and research I would like to update this blog post with some useful information and findings Kamil had. Thanks Kamil for sharing this with me!

If he was using asmlib driver, then it was included in UEK kernels up to UEK6. In UEK7 it is no longer included, as oracleasm-support will use new io_uring kernel call insted of oracleasm kernel module.

See the MOS note for the simple workaround to rename the old kernel, and then the patch can be installed flawlessly. Thanks to Rainer Moser for pointing me to this note, and for pushing the SR forward. Rainer confirmed that all works nicely now with 19.22 on OL9.

Perfect and nice blog post as lot of customers will be upgrading to ol 8.8 and may be tempted to use uek7. This post will make sure we do not fall into this trap. I will share this with oci dbaas team as well.

As everybody knows, Linux regroups several operating system families. The most popular Linux OS are Debian, Red Hat, or Suse. But each family has many derived Linux distributions. In November 2006, Oracle released the first version of its operating system, totally based on Red Hat Enterprise Linux: Enterprise Linux.

In Oracle Linux 5 Update 5, Oracle introduced a new Kernel: the UEK (for Unbreakable Enterprise Kernel). This kernel consists in an upgraded kernel, with specific features or enhancements for Oracle software. In Oracle Linux 5.5, the Red Hat kernel was still installed and started by default, the UEK and the kernel with bug fixes had both to be installed manually.

Since Oracle Linux 5 Update 6, the Oracle UEK has replaced the Red Hat kernel. It is installed and started by default, and the Red Hat kernel is just installed, but not enabled. The kernel with bug fixes remains uninstalled but still available for a manual install.

The following table lists all Oracle Linux releases, associated to the corresponding kernel(s) and release date (dates are approximations from information displayed on oss.oracle.com and wikipedia.org):

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