Configuring Operating Systems for Oracle Database on Linux

Guidelines for Linux Operating System Installation

Before installing Oracle software on Linux, complete the required operating system configuration, hardware checks, and supported-distribution requirements. Deploy the operating system according to your vendor’s security guidance and apply common security practices to establish a secure foundation.

Completing a Minimal or Default Linux Installation

Perform either a minimal or default Linux installation. Minimal installations require the Oracle Database Preinstallation RPM or manual installation of all required packages, while default installations include most dependencies and reduce manual verification; Oracle recommends retaining the default package selection rather than customizing RPMs.

About Oracle Linux with the Unbreakable Enterprise Kernel

Oracle Linux includes the Unbreakable Enterprise Kernel (UEK), which is optimized and tested for Oracle Database, middleware, hardware, and enterprise workloads, and Oracle strongly recommends using it. UEK is optional when strict RHEL kernel compatibility is required because Oracle Linux also provides a RHEL-compatible kernel; Ksplice can update the running kernel without rebooting.

Reviewing Operating System and Software Upgrade Best Practices

Before upgrading, document existing versions, patches, and configurations, review the applicable upgrade procedures and documentation, and back up all databases. Operating system upgrades can use manual file migration with control-file recreation and command-line database upgrades, or Export/Import with Data Pump, which is recommended for performance and new data type support; verify platform, kernel, and package compatibility, and observe Oracle ASM rolling-upgrade restrictions for clustered environments.

Restrictions for HugePages and Transparent HugePages Configurations

Oracle recommends disabling Transparent HugePages because dynamic memory allocation can cause access delays, performance problems, or RAC node restarts, while standard HugePages provide more predictable performance. If HugePages are enabled, reserve sufficient memory for all database SGAs and the Grid Infrastructure Management Repository, account for that memory when sizing swap, and ensure the allocation is large enough to prevent fallback to regular pages.

Setting and Disabling Transparent HugePages on UEK Kernels

Configure Transparent HugePages according to the UEK version: set it to madvise on UEK7 and later, and disable it on earlier UEK releases unless the system has subsequently been upgraded to UEK7 or later. Update the GRUB kernel parameters, regenerate the boot configuration, restart the system, and verify the active setting through the appropriate kernel interface; the preinstallation RPM performs the recommended configuration automatically.

Configuring HugePages on Linux

Enable standard HugePages by confirming kernel support, setting an appropriate memlock limit for the Oracle user, verifying the HugePage size and Oracle group ID, and configuring vm.hugetlb_shm_group persistently. After database creation, calculate the required page count from active shared-memory segments, set and persist vm.nr_hugepages, verify availability, and restart instances; reserve no more than 70 percent of RAM for HugePages and retain at least 30 percent for standard pages.

About Installation Fixup Scripts

Oracle Universal Installer can generate runfixup.sh scripts to correct incomplete prerequisite configuration, including kernel and shared-memory parameters, network limits, inventory permissions, group memberships, and shell limits, with changes applied both persistently and immediately. Fixup scripts do not replace full prerequisite verification; for Grid Infrastructure and RAC installations, CVU and the cluvfy utility provide additional automated or manual checks.

Additional Drivers and Software Packages for Linux

Optional Linux components include current PAM libraries for external scheduler authentication, OCFS2 for supported Oracle Linux cluster filesystems, required Messaging Gateway fixes, unixODBC 2.3.4 or later for Oracle ODBC drivers, LDAP packages for directory-dependent scripts, and platform-specific Java, compiler, COBOL, Python, and XDK environments. Web browsers are needed only for Enterprise Manager interfaces and must support JavaScript and the specified HTML and CSS standards; OCFS2, Messaging Gateway, and some development components have platform-specific support limitations.

Checking Kernel and Package Requirements for Linux

Identify the installed Linux distribution with release-information commands, verify the running kernel and required errata with uname -r, and compare the results with the Oracle Database support requirements. Query required RPMs with rpm -q or architecture-aware RPM queries, and install missing or outdated packages from the distribution media or vendor repositories.

Setting Clock Source for VMs on Linux x86-64

For Linux x86-64 virtual machines, Oracle recommends using the tsc clock source when available. Check available sources, set and verify tsc, add clocksource=tsc to the GRUB kernel command line, and regenerate the GRUB configuration so the setting persists after reboot.

Confirming Host Name Resolution

Ensure the database server hostname resolves through DNS, NIS, or a centrally maintained /etc/hosts file. Use ping with the short and fully qualified hostname as appropriate to verify successful name resolution before installation.

Using Automatic SSH Configuration During Installation

Configure passwordless SSH and SFTP between all cluster nodes because Oracle Universal Installer, configuration assistants, and Enterprise Manager use these services for remote commands and file transfers. OUI can configure SSH automatically for the installation account, but login profiles must not emit messages or run disruptive commands such as stty; if remote connections close during Clusterware installation, set LoginGraceTime 0 in the SSH daemon configuration on every node.

Verifying the Disk Input Output Scheduler on Linux 8 and Later Systems

Review the disk I/O scheduler used by ASM devices on Linux 8 and later, RHEL 8 and later, and SLES 15 and later, consulting the storage vendor for the optimal configuration. Oracle generally recommends mq-deadline for rotational disks and none for SSDs and NVMe devices; verify the active scheduler on every cluster node through the device queue interface.

Verifying the Disk Input Output Scheduler on Linux 7 Systems

Review the disk I/O scheduler for ASM devices on Linux 7, RHEL 7, and SLES 12, with storage-vendor guidance taking precedence. Oracle generally recommends deadline for rotational disks and none for SSDs and NVMe devices; verify the configured scheduler on each cluster node through the device queue interface.
Read More: Verifying the Disk Input Output Scheduler on Linux 7 Systems