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vi Commands

What is vi? The default editor that comes with the UNIX operating system is called vi (visual editor). The UNIX vi editor is a full screen editor and has two modes of operation: Command mode commands which cause action to be taken on the file, and Insert mode in which entered text is inserted into the file. In the command mode, every character typed is a command that does something to the text file being edited; a character typed in the command mode may even cause the vi editor to enter the insert mode. In the insert mode, every character typed is added to the text in the file; pressing the (Escape) key turns off the Insert mode. While there are a number of vi commands, just a handful of these is usually sufficient for beginning vi users. To assist such users, this Web page contains a sampling of basic vi commands. The most basic and useful commands are marked with an asterisk (* or star) in the tables below. With practice, these commands should become automatic. NO
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UNDO_RETENTION paramter

Starting in Oracle9i, rollback segments are re-named undo logs. Traditionally transaction undo information was stored in Rollback Segments until a commit or rollback statement was issued, at which point it was made available for overlaying. Best of all, automatic undo management allows the DBA to specify how long undo information should be retained after commit, preventing "snapshot too old" errors on long running queries. This is done by setting the UNDO_RETENTION parameter. The default is 900 seconds (5 minutes), and you can set this parameter to guarantee that Oracle keeps undo logs for extended periods of time. Rather than having to define and manage rollback segments, you can simply define an Undo tablespace and let Oracle take care of the rest. Turning on automatic undo management is easy. All you need to do is create an undo tablespace and set UNDO_MANAGEMENT = AUTO. However it is worth to tune the following important parameters The size of the UND
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ORATAB

"oratab" is a file created by Oracle in the /etc or /var/opt/oracle directory when installing database software. Originally ORATAB was used for SQL*Net V1, but lately is's being used to list the databases and software versions installed on a server. This file may contain comments staring with a pound signs (#) in column one, and data lines consisting of entries in the following format: database_sid:oracle_home_dir:Y|N - database_sid is the system id (SID) of an Oracle instances on the server. - Oracle_home_dir is the ORACLE_HOME directory associated with this instance. - The Y|N flags indicate if the instance should automatically start at boot time (Y=yes, N=no). Besides acting as a registry for what databases and software versions are installed on the server, ORATAB is also used for the following purposes: ◦Oracle's "dbstart" and "dbshut" scripts use this file to figure out which instances are to be start up or shut do
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Configuring SSH on Cluster Member Nodes

To configure SSH, you must first create RSA and DSA keys on each cluster node, and then copy the keys from all cluster node members into an authorized keys file on each node. Note that the SSH files must be readable only by root and by the oracle user. SSH ignores a private key file if it is accessible by others To configure SSH, complete the following steps: Create RSA and DSA keys on each node: Complete the following steps on each node: 1.Log in as the oracle user. 2.If necessary, create the .ssh directory in the oracle user's home directory and set the correct permissions on it: $ mkdir ~/.ssh $ chmod 700 ~/.ssh $ chmod 700 3.Enter the following commands to generate an RSA key for version 2 of the SSH protocol: $ /usr/bin/ssh-keygen -t rsa At the prompts: ◦Accept the default location for the key file. ◦Enter and confirm a pass phrase that is different from the oracle user's password. This command writes the public key to the ~/.ssh/id_rsa.pub
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Verifying That the User nobody Exists

Before installing the software, complete the following procedure to verify that the user nobody exists on the system: 1.To determine if the user exists, enter the following command: # id nobody If this command displays information about the nobody user, then you do not have to create that user. 2.If the nobody user does not exist, then enter the following command to create it: # /usr/sbin/useradd nobody
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Determining if an Oracle Software Owner User Exists

Determining if an Oracle Software Owner User Exists To determine whether an Oracle software owner user named oracle exists, enter the following command: # id oracle If the oracle user exists, then the output from this command is similar to the following: uid=440(oracle) gid=200(oinstall) groups=201(dba),202(oper)
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Oracle Validated Configuration RPM

About the Oracle Validated Configuration RPM If your Linux distribution is Oracle Linux, or Red Hat Enterprise Linux, and you are an Unbreakable Linux customer, then you can complete most preinstallation configuration tasks by using the Oracle Validated Configurations Setup RPM, available from the Unbreakable Linux Network, or available on the Oracle Linux DVD disks. When it is installed, the Oracle Validated Configuration RPM does the following: • Automatically installs any additional packages needed for installing Oracle Grid Infrastructure and Oracle Database • Creates an oracle user, and creates the oraInventory (oinstall) and OSDBA (dba) groups for that user • Sets and verifies sysctl.conf settings, system startup parameters, user limits, and driver parameters to values based on recommendations from the Oracle Validated Configurations program To become an Unbreakable Linux Network customer, contact your sales representative, or purchase a license from the Unbreakable
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