Dear
Readers,
My
name is Franz Devantier, creator of this blog. I am an Oracle Certified
Professional (OCP DBA 11g) Security DBA.
I will be sharing with you the basic duties of an Oracle DBA, and also
some of the undocumented, and not so well known tasks.
I will make a deal with you: If you refer me to a company that needs
database support, from a few hours per week to full time, and I am able to sign
a contract with them.
Then I will give you 10% of the
monthly contract or deal price every month.
When the contract ends, and we re-sign the contract, I will again give
you 10% of the monthly contract price.
This will go on until the company no longer employs or contracts me or
my agents to look after their databases.
I can do this, because that 10% is my
marketing budget. When we re-sign the
contract, in the future, it may depend on you giving the thumbs up again, and
that is worth 10% of the monthly contract price, to be given to you as
commission.
Oracle
Database Preinstallation – Part 12
Choosing a
Storage Option for Oracle Database and Recovery Files
The database files include
data files, control files, redo log files, server parameter file (spfile), and
the password file. If you are going to
enable automated backups during the installation, then you should also choose
the storage option for the recovery files.
The recovery files will be in the fast recovery area. You can use different storage options for
each file type. The good news in 11.2 is
that database files and recovery files are supported on file systems and Oracle
ASM. This means that we can go all for
ASM or file systems, or a combination of the two.
Guidelines for choosing your storage options.
=> You can implement on any combination of the
supported storage options, for each file type.
=> Decide whether you want to store your database
files, or your recovery files on Oracle ASM, or if you want to store both of
them on ASM.
Creating Directories for Oracle Database or
Recovery Files
Guidelines for Placing Oracle Database Files
on a File System
If you have chosen to put your database files on a file
system.
=> The default path that Oracle Universal Installer
(OUI) will suggest is a subdirectory of the Oracle Base Directory.
=> You can choose to store your database files on a
single file system, or on multiple file systems.
If you decide to go with a single file system, then you
should choose a file system on a physical device that is dedicated to the
database. For best performance and
reliability you should choose a RAID device, or you should choose a logical
volume that is housed on more than one physical device and implement the
stripe-and-mirror-everything (SAME) methodology.
If you decide to use
more than one file system, then choose file systems on separate physical
devices that are dedicated to the database.
Doing this allows you to distribute input-output operations and create
separate control files on different physical devices for increased
reliability. This arrangement also
allows you to fully implement the OFA guidelines. To implement this method, you can choose the
advanced database creation option.
=> If you are going to create a preconfigured database
during the installation, then the file system or file systems that you choose,
must have a minimum of 2GB of free disk space.
For a production database, you must estimate the disk space requirement depending
on how the database is to be used.
=> For optimum performance, the file systems that you
choose must be on physical devices that are used only by the database, no
compromise on this one.
=> The oracle user must have write permissions to
create the files in the path that you specify.
It is always good to create directories
for the Oracle database or recovery files on separate file systems from the
Oracle base directory.
=> determine the free disk
space on each mounted file system
$ df –h
Examine the output to
determine which are the best file-systems to use.
Database files: Choose either
a single file system, or multiple files systems.
Recovery files: Choose a file
system with at least 2.4 GB of free disk space
If you are going
to be using one file system for all the different file types, then you must add
the disk space requirements together for all of them, so that you can determine
the total disk space required.
Make a note of the names of
the mount point directories for the file systems that you identified. Then you will need to create the recommended
subdirectories in each of the mount point directories, and set the owner,
group, and permissions on them.
Database file directory
$ mkdir /<mount_point>/oradata
$ chown oracle:oinstall /<mount_point>/oradata
$ chmod 775 /<mount_point>/oradata
We have now moved the database
file directories away from the default file location which is
$ORACLE_BASE/oradata
Recovery file directory (fast recovery area)
$ mkdir /<mount_point>/fast_recovery_area
$ chown oracle:oinstall /<mount_point>/fast_recovery_area
$ chmod 775 /<mount_point>/fast_recovery_area
We have now moved the
recovery file directory away from the default of $ORACLE_BASE/fast_recovery_area. Having the recovery file directory and the
datafile directory on separate physical devices or disks, enables you to use
the recovery area, if something has gone wrong with the database file storage
area.
You can also use Oracle ASM
for storage.
Franz
Devantier,
Need
a database health check?
devantierf@gmail.com
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