Database Reference
In-Depth Information
Total System Global Area in large pages = 2514 MB (100%)
Large pages used by this instance: 1257 (2514 MB)
Large pages unused system wide = 143 (286 MB)
Large pages configured system wide = 1400 (2800 MB)
Large page size = 2048 KB
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It is possible that only a part of the SGA uses large pages, which is a scenario to be avoided. Setting the
initialization parameter “use_large_pages” to “only” as shown in the preceding example ensures that the SGA in its
entirety uses large pages. Please do not over-allocate large pages! Large pages affect only the SGA; private memory
structures such as the PGA and UGA do not benefit from them. You need to leave enough memory available on the
system for user sessions, or otherwise risk problems.
Introducing the oracle-rdbms-server preinstall package
Shortly after Oracle announced support for 11.2.0.3 on Oracle Linux 6 the company also released an updated RPM
to simplify the installation of the software for RAC and single instance. Similar to the well-known “oracle-validated”
RPM used with Oracle Linux 5, this new package performs many necessary pre-installation steps needed for Oracle
database 12c (a separate RPM is available for 11g Release 2). Among those performed is the creation of the oracle
account, modifying kernel and session related parameters. The package also modifies the kernel boot loader
configuration file. It is a great help when getting started with Oracle, but it is not foolproof. As with any piece of
software understanding the changes it makes to the operating system is crucial in configuring a robust system.
The preinstall RPMs are tied to a specific database version at the time of this writing, namely 11.2 and 12.1. During
testing it made no difference to the installation of the 12c database and Grid Infrastructure packages whether the 11g
Release 2 or 12c Release 1 RPM were installed. This is because the system requirements are very similar for both.
Before adding any of these packages to the default build, ensure that the package matches the build standard.
This is especially important with regards to the user and group IDs. If needed, you can always get the source RPM
(“SRPM”) file and modify the settings in it. In addition, none of the preinstall RPMs create a grid user for a separation
of duties, nor do they install the new operating system groups introduced in the earler section “Creating the operating
system users and groups”.
Configuring storage
In addition to the storage required to host the Oracle binaries, additional space is required for the actual Oracle
database. A number of choices exist for the underlying file system, including ASM. For each of them, the starting point
will be the logical unit number or LUN(s) to be presented to the host by the storage administrators. Most systems will
use multiple paths to the storage for performance and resilience. All major storage vendors have their own proprietary
multipathing software-EMC's PowerPath, Hitachi Dynamic Link Manager, and too many more to list here.
In addition to these proprietary drivers, Linux comes has its own generic multipathing package, called
dm-multipath . In the following section you will see how that is used in the context of an Oracle database installation.
Partitioning LUNs
Before beginning the multipathing configuration which is covered in the next section it is beneficial to partition the
devices at this stage. This prevents unloading and messing with the devices once the multipath configuration is in
place. Two utilities exist for partitioning: parted and fdisk . This section focusses on the fdisk utility.
 
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