Installing Oracle Linux 6 for DBAs

Being a DBA, it is good to be independent of system admin as much as you can because many times you could be in a situation where you need to install and/or manage the OS yourself and also need to suggest some OS tuning or parameter setting to run Oracle successfully on your system. Here I will be explaining how to install Oracle Linux 6 on a server

ORA-01653: unable to extend table by 8192 in tablespace

ORA-01653: unable to extend table <SCHEMA_NAME>.<SEGMENT_NAME> by 8192 in tablespace <TABLESPACE_NAME>

This error is quite common and it clearly means oracle was not able to allocate space to a segment and returned this error. Alert log file will show error similar to the following.

Wed May 31 17:15:28 2013 ORA-1653: unable to extend table SCOTT.TEST by 8192 in tablespace DATA_TBS

Creating Shared Disks for Oracle RAC on Oracle Virtual Box

If you want to do a test Oracle RAC (12c R1, 12c R2) installation on virtual machines you would need to create shared disks to be used across all the RAC nodes to store OCR/voteDisk and other ASM disks for database storage.
In the following, I will explain how we can created shared disks in Oracle Virtual Box.

Installing Oracle 12c Release 1 RAC on Linux 7

This article explains how to install a 2 nodes Oracle 12cR1 Real Application Cluster (RAC) on Oracle Linux 7. I did this installation on Oracle Virtual Box by creating 2 virtual machines with shared storage. OS platform I used is Oracle Enterprise Linux 7 (update 1), and Oracle GI and RDBMS version is 12.1.0.2. Same installation guide should work for Redhat Linux 7 also.

Configuring SSH for Oracle RAC installation

User equivalence is required on all nodes during Oracle RAC installation which provides OUI to log into all remote notes to perform copy/install the software and perform other configuration tasks. We can use different approaches to setup the passwordless ssh connectivity.

Using Cluster Verification Utility (cluvfy)

While installing RAC, cluster verification utility (cluvfy) is used to check whether all required prerequisites have been met, before proceeding to the Grid Infrastructure for RAC installation. 

We also use it after the installation to check if everything is working fine after the installation.

ORA-01157: cannot identify/lock data file

While starting up a database, you may face following error messages which would not allow you to open the database.

ORA-01157: cannot identify/lock data file <file#> - see DBWR trace file
ORA-01110: data file <file#>: <file_name>

Manual upgrading Oracle database 11g to 12c

If you want to know how we upgrade an 11g database to 12c using DBUA, click here. 

For upgrading 12.1.0.1 to 12.1.0.2 using DBUA, click here.

This article explains how to upgrade 11.2.0.2 and above, and 12.1.0.1 to 12.1.0.2 manually.

For details of each step, take a look at official 12c

ORACLE.EXE (SHAD) Processes Keep Increasing

On Windows based Oracle installations, if you hit an issue whereby you see that processes/sessions keep increasing unabated, and you keep receiving “ORA-00020: maximum number of processes exceeded” error while connecting to the database and increasing the value of parameter “processes” remains insufficient always,

ORA-00020: maximum number of processes exceeded

You may face this error message while connecting to the database instance which will also hinder you from connecting with the database instance. The reason of this error is the value of init parameter “processes” which requires to be increased to allow Oracle instance to span a new process for new session request. For example, if value of this parameter is set to 100,