One of the pillars of today's technology is communication and data. Most important are how fast you can communicate with other people and how fast you can retrieve data, and they tremendously influence people's lives in this modern era. Technologies may come and go, but the fundamentals of databases still prevail, and the power of databases will not fade away anywhere in the future.
Oracle database is one such RDBMS built on robust technology and is still considered one of the market-dominant leaders. This article concerns upgrading the Oracle database from a lower to a higher version. Instead of a seamless transition, if the database upgrade takes a U-turn, causing disruptions, then what would you do? Or at least what would you have done to prevent this catastrophe? Let’s delve into the pre-upgrade tasks for a smooth transition.
Oracle Database Upgrade Checklist
You must follow specific steps when upgrading the existing database from a lower version to a higher version. For Example, If your organization has any Oracle databases running on ancient versions, such as 9.x/10.x/some 11.x, as per Oracle’s recommendations and Best Practices, you are not allowed to upgrade to the latest version directly. Here, I have referenced Oracle 19c as one of the latest versions released by Oracle in 2019.
The above illustration says what is not allowed during a database upgrade. If this is not allowed, then what is allowed? For that, let’s delve into the illustrations below and explore several options and Best Practices Oracle recommends.
From the above illustration, Oracle supports a direct database upgrade if your Oracle database is running on versions 11.2.04/12.1.0.2/12.2.0.1/18.1 directly to 19c. But what if your database is not running on these versions? Well, there is a solution for every issue. Let’s explore the options below and see if any of these suit your company’s policies and regulations.
Oracle doesn’t support a direct database upgrade if your source database runs on 9.x/10.x/certain versions of 11.x/certain versions of 12.x to Oracle 19c. To resolve this, Oracle has introduced a multi-step upgrade process. In this scenario, you would upgrade your source database to an Intermediate release supported by Oracle, then Upgrade the Intermediate release version to the Target Oracle 19c.
The above illustration conveys the following. When you upgrade, find out bits and pieces of your Oracle database.
If you are upgrading from the Oracle database version 9.x or earlier to Oracle 19c, then you must first upgrade to the Oracle database version 11.2.0.4, then to 19c.
If you are upgrading from version 10.1.x/10.2.x, then first, you must upgrade to 11.2.0.4, then from 11.2.0.4 to 19c.
If your database is 11.1.0.6, 11.1.0.7/11.2.0.1, 11.2.0.2, and 11.2.0.3, you must first upgrade to Intermediate version 11.2.0.4. From 11.2.04 to 19c is the direct upgrade.
Finally, if your database is on version 12.1.0.1, first upgrade to Intermediate version 12.1.0.2 or 12.2.0.1, then a direct upgrade to 19c.
Note: This doesn’t apply to the upgrade process involving Oracle data pump export/import to migrate the data to the new Oracle database release.
Should you do anything to your OS before upgrading your source database?
The simple answer is Yes. You must ensure that your operating system meets the prerequisites to install or upgrade the source database to 19c. The following must be carefully drafted and validated thoroughly.
Check whether the Operating System is compatible with the Intermediate version of the Oracle database and also with Oracle database version 19c.
Take a backup of the root bash profile, Oracle user bash profile, and any cron jobs the Oracle user executes.
/etc/oratab
/etc/oraInst.locOpen a service request to Oracle support and explain your situation. Take suggestions from them before applying any patches or starting the upgrade process.
Review the Oracle documentation for any prerequisites for your operating system.
As per the Oracle documentation, Upgrade your operating system or apply any required patches.
Ensure OpenSSH is installed, configured on the servers, and accessible from the network.
Open any related firewalls for ports on the database server if needed.
If your operating system is RHEL, it must be
Red Hat Enterprise Linux 9: 5.14.0-70.22.1.el9_0.x86_64 or later, Red Hat Enterprise Linux 8: 4.18.0-80.el8.x86_64 or later, Red Hat Enterprise Linux 7.5: 3.10.0-862.11.6.el7.x86_64 or later.If your operating system is Oracle Linux, then it must be
Oracle Linux 9 with the Unbreakable Enterprise Kernel 7: 5.15.0-1.43.4.2.el9uek.x86_64 or later, Oracle Linux 9 with the Red Hat Compatible Kernel: 5.14.0-70.22.1.0.2.el9_0.x86_64 or later, Oracle Linux 8.1 with the Unbreakable Enterprise Kernel 6: 5.4.17-2011.0.7.el8uek.x86_64 or later, Oracle Linux 8 with the Red Hat Compatible kernel: 4.18.0-80.el8.x86_64 or later.If you use Oracle Linux, Oracle recommends running the Oracle Database Preinstallation RPM for your Oracle Linux release to configure the operating system for Oracle Database and Oracle Grid Infrastructure installations.
Linux Server Configuration
Make sure the /tmp directory space has atleast 1GB in free.
Swap space allocation must be relative to the allocated physical or virtual RAM.
If you have already installed the Oracle database on your servers, all the information related to the installed binaries is in the file “/etc/oraInst.loc."
If you try to upgrade the Oracle database, the installer automatically detects the Oracle-installed directories based on the information from the/etc/oraInst.loc file.
Oracle database upgrade is not an easy task. There must be thorough due diligence to be put in before and after the upgrade. Careful planning, design, deployment, and validation are mandatory. The above chart shows a glimpse of what goes into an Oracle upgrade process. This chart is not a complete set of steps, but it is mentioned to mention what and how an Oracle upgrade will happen.
In Part -2 of this article, we will dig into deep a step-by-step process of upgrading the database.
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