Transparent HugePages memory is enabled by default with Oracle Linux 6 and later,Red Hat Enterprise Linux 6 and later, SUSE 11 and later, kernels.Transparent Hugepages are similar to standard HugePages. However, while standardHugePages allocate memory at startup, Transparent Hugepages memory uses thekhugepagedthread in the kernel to allocate memory dynamically during runtime, usingswappable HugePages.HugePages allocates non-swappable memory for large page tables using memory-mapped files. HugePages are not enabled by default. If you enable HugePages, thenyou should deduct the memory allocated to HugePages from the available RAM beforecalculating swap space. Refer to your distribution documentation and to Oracle Tech‐nology Network and My Oracle Support for more information.During Oracle Grid Infrastructure installation, the Grid Infrastructure Management Re‐pository (GIMR) is configured to use HugePages. Because the Grid InfrastructureManagement Repository database starts before all other databases installed on thecluster, if the space allocated to HugePages is insufficient, then the System GlobalChapter 4Guidelines for Linux Operating System Installation4-6
Area (SGA) of one or more databases may be mapped to regular pages, instead ofHugepages, which can adversely affect performance. Configure the HugePages mem‐ory allocation to a size large enough to accommodate the sum of the SGA sizes of allthe databases you intend to install on the cluster, as well as the Grid InfrastructureManagement Repository.Related Topics•Oracle Database Administrator's Reference for Linux and UNIX-Based OperatingSystemsReviewing Operating System and Software Upgrade BestPracticesThese topics provide general planning guidelines and platform-specific informationabout upgrades and migration.•General Upgrade Best PracticesBe aware of these guidelines as a best practice before you perform an upgrade.•New Server Operating System Upgrade OptionYou can upgrade your operating system by installing a new operating system on aserver, and then migrating your database either manually, or by using Export/Import method.•Oracle ASM Upgrade NotificationsUnderstand Oracle ASM upgrade options and restrictions.General Upgrade Best PracticesBe aware of these guidelines as a best practice before you perform an upgrade.If you have an existing Oracle Database installation, then do the following:•Record the version numbers, patches, and other configuration information•Review upgrade procedures for your existing installation•Review Oracle Database upgrade documentation before proceeding with installa‐tion, to decide how you want to proceedCaution:Always create a backup of existing databases before starting any configura‐tion change.