Transparent HugePages memory is enabled by default with Oracle Linux 6 and

Transparent hugepages memory is enabled by default

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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 standard HugePages allocate memory at startup, Transparent Hugepages memory uses the khugepaged thread in the kernel to allocate memory dynamically during runtime, using swappable HugePages. HugePages allocates non-swappable memory for large page tables using memory- mapped files. HugePages are not enabled by default. If you enable HugePages, then you should deduct the memory allocated to HugePages from the available RAM before calculating 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 Infrastructure Management Repository database starts before all other databases installed on the cluster, if the space allocated to HugePages is insufficient, then the System Global Chapter 4 Guidelines for Linux Operating System Installation 4-6
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Area (SGA) of one or more databases may be mapped to regular pages, instead of Hugepages, 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 all the databases you intend to install on the cluster, as well as the Grid Infrastructure Management Repository. Related Topics Oracle Database Administrator's Reference for Linux and UNIX-Based Operating Systems Reviewing Operating System and Software Upgrade Best Practices These topics provide general planning guidelines and platform-specific information about upgrades and migration. General Upgrade Best Practices Be aware of these guidelines as a best practice before you perform an upgrade. New Server Operating System Upgrade Option You can upgrade your operating system by installing a new operating system on a server, and then migrating your database either manually, or by using Export/ Import method. Oracle ASM Upgrade Notifications Understand Oracle ASM upgrade options and restrictions. General Upgrade Best Practices Be 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 proceed Caution: Always create a backup of existing databases before starting any configura‐ tion change.
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