Saturday, December 31, 2016

OEM Cloud Control Job Suspended - Target is not ready

In my OEM 12c, my RMAN backup job for one target database started failing, and next execution status was marked as "Suspended".







Wednesday, October 26, 2016

DUPLICATE Database using Backup of a Database

If you want to create a duplicate database from a live/active database, you can follow this article. But if you want to DUPLICATE a database using backup of another database, you can use following steps. I am creating new database with a different name using DUPLICATE command, or you may want to retain same name for the database while duplicating.

Friday, October 14, 2016

Configuring OEM Express Control

Starting 12c, OEM Database Control has been replaced by OEM Database Express. OEM Express configuration is very simple as compared to previous OEM Database Control. Following is the method to configure OEM Express. OEM Express Database is configured separately for container database and each pluggable database. Method is same; you just need to set current container to pluggable database for which you want to configure the OEM, and execute the steps as explained bellow.

Tuesday, October 4, 2016

Calculating ASM diskgroup Usable Size

Sometimes sizing information of an ASM diskgroup returned by “lsdg” command from “asmcmd” prompt (similar information is also available under v$asm_diskgroup view) leaves DBAs perplexed. Sizing information and usable space for diskgroups with EXTERNAL REDUNDANCY is quite easy to understand, but when it comes to NORMAL or HIGH redundancy diskgroups, it is not very straightforward. Here I would explain ASM diskgroup space calculation in detail to make it easier to understand. Before I explain how to calculate usable space in an ASM diskgroup, some useful information to note is as follows

Tuesday, September 20, 2016

Linux Error: No Space Left on Device

On Linux machine, there could be several reasons for this error message appearing in some log file, or on the command line output while executing some command. Most of the time we immediately start checking if our file system has still sufficient space left, but file system space is not the problem most of the time. Following are a few of them I will be discussing.

Monday, September 12, 2016

Enable Asynchronous IO for file System

We noticed that on one of our standby database, the log apply was quite slow. I stopped managed recovery process which showed ORA-16037 in the alert log file along with trace file name.
ALTER DATABASE RECOVER managed standby database cancel
Fri Nov 20 16:13:12 2015
RFS[2]: Selected log 12 for thread 1 sequence 504809 dbid -1228626264 branch 748801133
Fri Nov 20 16:13:13 2015

Thursday, August 11, 2016

Backing up OEM Cloud Conrol 12c, 13c

Just like any other application or database deployment, we should also devise a backup and recovery policy for the OEM deployments. Here I would discuss how we devise a backup policy to back up our OEM 13c (and also previous versions) deployment. Following are the major components that should be considered for the backup. Official documentation explains this in more detail

Sunday, July 17, 2016

Starting and Stopping OEM Cloud Control 13c

After you have installed OEM Cloud Control 13c, you should know how to start and stop the OEM components. Here I will explain the sequence of starting and stopping OEM 13c components and same steps could be used for starting and stopping OEM cloud control 12c. For this example, my $ORACLE_HOME (OEM repository database home) is /u01/app/oracle/product/12.1.0/db, $OMS_HOME is /u01/software/em/middleware, and $AGENT_HOME is

Thursday, June 16, 2016

Installing OEM 13c on Linux 6 and 7

In this article I will explain how to install Oracle Enterprise Manager 13c on Linux 6 and 7. Installation process is almost similar for both Linux 6 and 7. I am using Oracle Enterprise Linux for this installation. Recommended way is to install database repository on a separate server and OMS on a different server, but for this installation I will be using a single server for both repository and OMS installation. You may download OEM 13c from www.oracle.com. Latest downloadable version available while writing this article is 13.1.0.0. Download all 5 files as shown below.

Tuesday, May 31, 2016

Installing Oracle 12c R1 Grid Infrastructure on Linux 7

You might be interested in installing 12cR1 Grid Infrastructure (for a standalone server) software in order to use ASM and/or Oracle Restart feature of GI. In the following I will explain how to install GI for a standalone server on Linux 7. For this installation, I am using Oracle Linux 7. You might also want to check how to install Oracle 12cR1 GI on Linux 6

Sunday, May 22, 2016

Installing Oracle 12c R1 Grid Infrastructure on Linux 6

You might be interested in installing 12c R1 Grid Infrastructure (for a standalone server) software in order to use ASM and/or Oracle Restart feature of GI. In the following I will explain how to install GI for a standalone server on Linux 6. For this installation, I am using OracleLinux 6You might also want to check how to install Oracle 12c R1 GI on Linux 7

Thursday, May 5, 2016

Configuring oracleasmLib On Linux

To use ASM on Linux, we need to create ASM disks, and using oracleasmLib is one way to configure ASM disks. To do this, we need to install oracleasm kernel driver, oracleasm-support and oracleasmlib, and then configure oracleasm.
oracleasm kernel driver is built in Oracle Linux and does not need to be installed. After installing oracleasm-support and oracleasmlib packages, oracleasm driver starts working.

Wednesday, April 27, 2016

Installing Oracle 12c R1 Database Software on Linux 7

This document explains how to install Oracle 12c Database software on Oracle Linux 6. At the time of writing this document, latest 12c version is 12.1.0.2 which can be downloaded from My Oracle Support using patch search for patch 17694377 (Disk 1 and Disk 2 are needed for Oracle Database software). Otherwise you can also download 12.1.0.1 from www.oracle.com.

Tuesday, April 12, 2016

Installing Oracle 12c R1 Database Software on Linux 6

This document explains how to install Oracle 12cR1 Database software on Oracle Linux 6. At the time of writing this document, latest 12c version is 12.1.0.2 which can be downloaded from My Oracle Support using patch search for patch 17694377 (Disk 1 and Disk 2 are needed for Oracle Database software). Otherwise you can also download 12.1.0.1 from www.oracle.com

Tuesday, March 22, 2016

Creating Oracle Database Using dbca for 12c R1

Database Configuration Assistant (dbca) is an Oracle provided tool to create a new database. In this document I would explain how to create a new 12c R1 database using dbca. For database creation steps for Oracle 12c R2, follow this document. Steps and screens are almost same for other Oracle database versions and different OS platforms.

Monday, March 14, 2016

Changing Listener and SCAN Listener Ports

In this article I will explain how we modify Listener and SCAN Listener ports in RAC environment. For this article, in a 2 nodes RAC on Windows, my database listeners are listening ports 1521 and scan listeners are running on port 1522. I will change listeners’ ports to 1531 and scan listeners’ ports to 1532.

Wednesday, March 2, 2016

ORA-01017: invalid username/password - While Starting Instance using srvctl

If you face ORA-01017, following could be the reasons of this error.
  • Username has been specified wrongly – check the username.
  • Password has been specified wrongly – check the password.
  • If you see this error while logging in as user SYS, check if password file exists. If not, re-create the password file or enable OS authentication.

Thursday, February 18, 2016

Starting and Stopping Oracle Cluster (RAC)

In this article I will explain how to start and stop a cluster (RAC).
We can either use “crsctl stop/start cluster” command or “cractl start/stop crs” command to accomplish this task. The difference between both method is as follows

Friday, February 5, 2016

CRS-4563: Insufficient user privileges

[grid@dbnode1 ~]$ crsctl start crs
CRS-4563: Insufficient user privileges.

CRS-4000: Command Start failed, or completed with errors.

Wednesday, January 27, 2016

CRS-4535: Cannot communicate with Cluster Ready Services

If checking status of CRS (and other RAC resources) returns you this error, it means that CRS is not running.
[grid@dbnode1 ]$ crsctl stat res -t
CRS-4535: Cannot communicate with Cluster Ready Services
CRS-4000: Command Status failed, or completed with errors.

Thursday, January 14, 2016

OEM Database Control Configuration gets Stuck

I encountered a situation where I was trying to configure OEM Database Control (11.2.0.4) on Windows based system using command similar to the following
emca -config dbcontrol db -repos recreate

Monday, January 4, 2016

ORA-00221: error on write to controlfile

Reason of this error (and probably instance crash) is that some other process has locked the controlfile and oracle process is not able to get hold of a lock on the controlfile before it could write in it. Most probable reason for this is some third party backup solution that might be copying oracle related files in backup process and hence holding a lock while copying.