Database Administrator

Basic Enterprise Manager Troubleshooting

The web-based Enterprise Manager tool was introduced in Oracle 10g and has significant functionality improvements over previous versions. Even so, it seems there is not a day goes by without someone asking how to solve an Enterprise Manager configuration issue, so this article explains the first things you should look at. It's not meant to be an all encompassing guide. Just a first shot.
Make sure the "/etc/hosts" file contains at least the loopback address and preferably the machine definition also.

127.0.0.1       localhost.localdomain  localhost
192.168.0.181   myserver.localdomain   myserver

If you are using 11g, make sure the ORACLE_HOSTNAME and ORACLE_UNQNAME environment variables are set correctly.

ORACLE_HOSTNAME=myserver.localdomain; export ORACLE_HOSTNAME
ORACLE_UNQNAME=DB11G; export ORACLE_UNQNAME

Check the listener is running correctly.

lsnrctl status

Manual Upgrades

Backup the database before starting the upgrade process. In the event of a failure, you will need this backup to allow you to recreate your starting point.
To run the new Pre-Upgrade Information Tool, copy the "preupgrd.sql" and "utluppkg.sql" scripts from the 12c home to a location accessible by the database that needs upgrading. In this example I used a directory under "/tmp".

$ mkdir -p /tmp/upgrade
$ cp /u01/app/oracle/product/12.1.0.1/db_1/rdbms/admin/preupgrd.sql /tmp/upgrade
$ cp /u01/app/oracle/product/12.1.0.1/db_1/rdbms/admin/utluppkg.sql /tmp/upgrade

Make sure the ORACLE_BASE is set and run the "preupgrd.sql" script from SQL*Plus.

$ export ORACLE_SID=orcl
$ ORAENV_ASK=NO
$ . oraenv
$ ORAENV_ASK=YES
$ cd /tmp/upgrade
$ sqlplus / as sysdba

SQL> @preupgrd.sql
Loading Pre-Upgrade Package...
Executing Pre-Upgrade Checks...
Pre-Upgrade Checks Complete.
      ************************************************************

Supported Upgrade Paths

Direct upgrades to 12c are possible from existing databases with versions 10.2.0.5+, 11.1.0.7+, or release 11.2.0.2+. Upgrades from other versions are supported only via intermediate upgrades to a supported upgrade version.
When you are using the DBUA or performing a manual upgrade, you will need both versions of the database present to complete the operation. Typically, you will be installing Oracle 12c into a new ORACLE_HOME on the existing server.

Database Upgrade Assistant (DBUA)

The preferred upgrade method is to use the Database Upgrade Assistant (DBUA), a GUI tool that performs all necessary prerequisite checks and operations before upgrading the specified instances. The DBUA can be started directly from the Oracle Universal Installer (OUI) during installation, or separately after the software installation is complete.
Make sure the database is started and run the database upgrade assistant.

$ export ORACLE_HOME=/u01/app/oracle/product/12.1.0.1/db_1
$ export PATH=$ORACLE_HOME/bin:$PATH
$ dbua

Select the "Upgrade Oracle Database" option, then click the "Next" button.
Select Operation

Purpose

This article provides steps to power on virtual machines from the command line (either through the ESX host console or through the RCLI/vSphere CLI) if the host cannot be managed from vCenter Server or from vSphere Client.

Resolution

Note: The steps in this article require root access to the host, either at the physical console or using SSH. For more information on enabling root access, see:

ESXi 5.x

To power on a virtual machine from the command line:

List the inventory ID of the virtual machine with the command:

vim-cmd vmsvc/getallvms |grep <vm name>
Note: The first column of the output shows the vmid.
Check the power state of the virtual machine with the command:

vim-cmd vmsvc/power.getstate <vmid>
Power-on the virtual machine with the command:

vim-cmd vmsvc/power.on <vmid>

Sharing Files between RHEL 6 and Windows Systems with Samba

Samba and Samba Client

Samba allows both RHEL resources to be shared with Windows systems and Windows resources to be shared with RHEL systems. RHEL accesses Windows resources using a package named samba-client. RHEL resources, on the other hand, are shared with Windows systems using a package named samba. Typically, the samba-client is installed and configured by default allowing you to browse available Windows resources without any additional work (this is covered later in the chapter). In order to allow an RHEL 6 system to share resources with Windows systems, however, some more work is required.

Installing Samba on an RHEL 6 System

The default settings used during the RHEL 6 installation process do not install the samba package. Unless you specifically requested that Samba be installed it is unlikely that you have Samba installed on your system. To check whether Samba is installed, open a terminal window (Applications -> System Tools -> Terminal) and run the following rpm command:

rpm -q samba

If Samba is installed, the rpm command will generate output similar to the following:

samba-3.5.4-68.el6_0.1.x86_64

If Samba is not installed, rpm will return with "package samba is not installed". That being the case, it can be installed using the yum command-line tool:

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