Install Oracle 11g Express (XE) on CentOS

This post will cover basic installation and configuration of Oracle 11g Express Edition (XE) on CentOS.

We will also take a quick look at configuring Application Express (APEX) for 11g XE.

Basic installation is straight forward.

If you just want to get up and running, you can just do steps 1 to 4 below (and 10 and 11 for Apex). The remaining steps (5 to 9) cover basic backup, recovery, and performance configuration.

The full system requirements are here


Your CentOS box should have swap equal to 2xRAM.

On every CentOS installation I have done for XE, I just needed to update/install the packages for libaio, bc, and flex.

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1. [root@ms3 ~]#  yum install libaio bc flex  

Step 1: Download and Install Oracle 11g XE rpm

You can download the Oracle XE rpm, oracle-xe-11.2.0-1.0.x86_64.rpm.zip, from the OTN here

Unzip oracle-xe-11.2.0-1.0.x86_64.rpm.zip:

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1. [root@ms3 ~]# unzip -q oracle-xe-11.2.0-1.0.x86_64.rpm.zip  

This will create the directory Disk1. Change to the Disk1 directory:

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1. [root@ms3 ~]# cd Disk1  
2. [root@ms3 Disk1]# ls  
3. oracle-xe-11.2.0-1.0.x86_64.rpm  response  upgrade  

Install the rpm using rpm -ivh oracle-xe-11.2.0-1.0.x86_64.rpm

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1. [root@ms3 Disk1]# rpm -ivh oracle-xe-11.2.0-1.0.x86_64.rpm  
2. Preparing...                ########################################### [100%]  
3.    1:oracle-xe              ########################################### [100%]  
4. Executing post-install steps...  
5. You must run '/etc/init.d/oracle-xe configure' as the root user to configure the database.  
6.   
7. [root@ms3 Disk1]#  

Step 2: Configure 11g XE Database and Options

When installation completes, run '/etc/init.d/oracle-xe configure' to configure and start the database.

Unless you wish to change the ports, except the defaults and set SYS/SYSTEM password.

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1. [root@ms3 Disk1]# /etc/init.d/oracle-xe configure  
2.   
3. Oracle Database 11g Express Edition Configuration  
4. -------------------------------------------------  
5. This will configure on-boot properties of Oracle Database 11g Express  
6. Edition.  The following questions will determine whether the database should  
7. be starting upon system boot, the ports it will use, and the passwords that  
8. will be used for database accounts.  Press <enter> to accept the defaults.  
9. Ctrl-C will abort.  
10.   
11. Specify the HTTP port that will be used for Oracle Application Express [8080]:  
12.   
13. Specify a port that will be used for the database listener [1521]:  
14.   
15. Specify a password to be used for database accounts.  Note that the same  
16. password will be used for SYS and SYSTEM.  Oracle recommends the use of  
17. different passwords for each database account.  This can be done after  
18. initial configuration:  
19. Confirm the password:  
20.   
21. Do you want Oracle Database 11g Express Edition to be started on boot (y/n) [y]:y  
22.   
23. Starting Oracle Net Listener...Done  
24. Configuring database...Done  
25. Starting Oracle Database 11g Express Edition instance...Done  
26. Installation completed successfully.</enter>  

The installation created the directory /u01 under which Oracle XE is installed.

Step 3: Set the Environment

To set the required Oracle environment variables, use the oracle_env.sh the script included under cd /u01/app/oracle/product/11.2.0/xe/bin

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1. [root@ms3 Disk1]# cd /u01/app/oracle/product/11.2.0/xe/bin  

To set the environment for your current session run '. ./oracle_env.sh':

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1. [root@ms3 bin]# . ./oracle_env.sh  

To set the environment permanently for users, add the following to the .bashrc or .bash_profile of the users you want to access the environment:

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1. . /u01/app/oracle/product/11.2.0/xe/bin/oracle_env.sh  

You should now be able to access SQL*Plus

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1. [root@ms3 bin]# sqlplus /nolog  
2.   
3. SQL*Plus: Release 11.2.0.2.0 Production on Wed Sep 21 08:17:26 2011  
4.   
5. Copyright (c) 1982, 2011, Oracle.  All rights reserved.  
6.   
7. SQL> connect sys/Password as sysdba  
8. Connected.  
9. SQL>  

Step 4: Allow Remote Access to Oracle 11g XE GUI

To allow remote access to Oracle 11g XE GUI (as well as Application Express GUI) issue the following from SQL*Plus

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1. SQL> EXEC DBMS_XDB.SETLISTENERLOCALACCESS(FALSE);  
2.   
3. PL/SQL procedure successfully completed.  

You should now be able to access the Oracle 11g XE Home Page GUI at:

http://localhost:8080/apex/f?p=4950:1

Replace localhost above with your IP or domain as required.

Log in as SYSTEM using the password you selected in Step 2 above.

Step 5: Move the Flash Recovery Area (Fast Recovery Area)

To protect against disk failure, you should move the Flash Recovery Area to a separate disk.

This is actually now called the Fast Recovery Area, but the existing documentation still refers to it as the Flash Recovery Area

If a separate disk is not in your budget you should, at the very least, move the Flash Recovery Area to a partition other than the Oracle installation directory.

By default, the Fast Recovery Area will be located under /u01/app/oracle/fast_recovery_area

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1. SQL> show parameter DB_RECOVERY_FILE_DEST;  
2.   
3. NAME                                 TYPE        VALUE  
4. ------------------------------------ ----------- ------------------------------  
5. db_recovery_file_dest                string      /u01/app/oracle/fast_recovery_area  
6. db_recovery_file_dest_size           big integer 10G  
7. SQL>  

So, to move it elsewhere, first create the new directory

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1. [root@ms3 ~]# mkdir /opt/fra  

Change the owner to oracle and the group to dba

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1. [root@ms3 ~]# chown oracle:dba /opt/fra  

Now, change the DB_RECOVERY_FILE_DEST to the location you selected above.

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1. SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST = '/opt/fra';  
2.   
3. System altered.  
4.   
5. SQL>  

To move the files use the movelog.sql script:

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1. SQL> @?/sqlplus/admin/movelogs  
2. SQL> SET FEEDBACK 1  
3. SQL> SET NUMWIDTH 10  
4. SQL> SET LINESIZE 80  
5. SQL> SET TRIMSPOOL ON  
6. SQL> SET TAB OFF  
7. SQL> SET PAGESIZE 100  
8. SQL> declare  
9.   2     cursor rlc is  
10.   3        select group# grp, thread# thr, bytes/1024 bytes_k  
11.   4          from v$log  
12.   5        order by 1;  
13.   6     stmt     varchar2(2048);  
14.   7     swtstmt  varchar2(1024) := 'alter system switch logfile';  
15.   8     ckpstmt  varchar2(1024) := 'alter system checkpoint global';  
16.   9  begin  
17.  10     for rlcRec in rlc loop  
18.  11    stmt := 'alter database add logfile thread ' ||  
19.  12                 rlcRec.thr || ' size ' ||  
20.  13                 rlcRec.bytes_k || 'K';  
21.  14        execute immediate stmt;  
22.  15        begin  
23.  16           stmt := 'alter database drop logfile group ' || rlcRec.grp;  
24.  17           execute immediate stmt;  
25.  18        exception  
26.  19           when others then  
27.  20              execute immediate swtstmt;  
28.  21              execute immediate ckpstmt;  
29.  22              execute immediate stmt;  
30.  23        end;  
31.  24        execute immediate swtstmt;  
32.  25     end loop;  
33.  26  end;  
34.  27  /  
35.   
36. PL/SQL procedure successfully completed.  
37.   
38. SQL>  
39. SQL>  

Now, set an appropriate size for the Fast Recovery Area. Use df -h to insure that there is ample space.

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1. SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE = 20G;  
2.   
3. System altered.  

Verify the new location and size.

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1. SQL> show parameter DB_RECOVERY_FILE_DEST;  
2.   
3. NAME                                 TYPE        VALUE  
4. ------------------------------------ ----------- ------------------------------  
5. db_recovery_file_dest                string      /opt/fra  
6. db_recovery_file_dest_size           big integer 20G  
7. SQL>  

Step 6: Add Redo Log Members to Groups

You should have at least two Redo Log Groups and each group should have at least two members.

Additionally, the members should be spread across disks (or at least directories)

For whatever reason, only one member is created per group on install.

You can view the redo log files using SQL> SELECT * FROM V$LOGFILE;

Since the default location for the two members is the Flash Recovery Area, the two existing members have been moved to our new FRA.

You should now add an additional member for each group under /u01/app/oracle/oradata/XE

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1. SQL> ALTER DATABASE ADD LOGFILE MEMBER '/u01/app/oracle/oradata/XE/log1b.LOG' TO GROUP 1;  
2.   
3. Database altered.  
4.   
5. SQL> ALTER DATABASE ADD LOGFILE MEMBER '/u01/app/oracle/oradata/XE/log2b.LOG' TO GROUP 2;  
6.   
7. Database altered.  
8.   
9. SQL>  

Step 7: Set Sessions and Processes Parameters

The default values for parameters and sessions is quite low on the default installation.

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1. SQL> show parameters sessions;  
2.   
3. NAME                                 TYPE        VALUE  
4. ------------------------------------ ----------- ------------------------------  
5. java_max_sessionspace_size           integer     0  
6. java_soft_sessionspace_limit         integer     0  
7. license_max_sessions                 integer     0  
8. license_sessions_warning             integer     0  
9. sessions                             integer     172  
10. shared_server_sessions               integer  
11.   
12. SQL> show parameters processes;  
13.   
14. NAME                                 TYPE        VALUE  
15. ------------------------------------ ----------- ------------------------------  
16. aq_tm_processes                      integer     0  
17. db_writer_processes                  integer     1  
18. gcs_server_processes                 integer     0  
19. global_txn_processes                 integer     1  
20. job_queue_processes                  integer     4  
21. log_archive_max_processes            integer     4  
22. processes                            integer     100  

You can increase these parameters.

After each change, you will need to restart the database.

Increase sessions and then bounce database.

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1. SQL> alter system set sessions=250 scope=spfile;  
2.   
3. System altered.  
4.   
5. SQL> shutdown immediate  
6. Database closed.  
7. Database dismounted.  
8. ORACLE instance shut down.  
9. SQL> startup  
10. ORACLE instance started.  
11.   
12. Total System Global Area 1068937216 bytes  
13. Fixed Size                  2233344 bytes  
14. Variable Size             780143616 bytes  
15. Database Buffers          281018368 bytes  
16. Redo Buffers                5541888 bytes  
17. Database mounted.  
18. Database opened.  

Verify change to sessions parameter:

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1. SQL> show parameters sessions;  
2.   
3. NAME                                 TYPE        VALUE  
4. ------------------------------------ ----------- ------------------------------  
5. java_max_sessionspace_size           integer     0  
6. java_soft_sessionspace_limit         integer     0  
7. license_max_sessions                 integer     0  
8. license_sessions_warning             integer     0  
9. sessions                             integer     252  
10. shared_server_sessions               integer  

Increase processes and restart database

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1. SQL> alter system set processes=200 scope=spfile;  
2.   
3. System altered.  
4.   
5. SQL>  
6.   
7.   
8. Database dismounted.  
9. ORACLE instance shut down.  
10. SQL> startup  
11. ORACLE instance started.  
12.   
13. Total System Global Area 1068937216 bytes  
14. Fixed Size                  2233344 bytes  
15. Variable Size             763366400 bytes  
16. Database Buffers          297795584 bytes  
17. Redo Buffers                5541888 bytes  
18. Database mounted.  
19. Database opened.  

Verify change to processes parameter:

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1. SQL>  show parameters processes;  
2.   
3. NAME                                 TYPE        VALUE  
4. ------------------------------------ ----------- ------------------------------  
5. aq_tm_processes                      integer     0  
6. db_writer_processes                  integer     1  
7. gcs_server_processes                 integer     0  
8. global_txn_processes                 integer     1  
9. job_queue_processes                  integer     4  
10. log_archive_max_processes            integer     4  
11. processes                            integer     200  
12. SQL>  

Step 8: Enable Archivelog Mode

To enable online or "hot" backups, Archivelog Mode must be enabled.

Additionally, if you do not enable Archivelog Mode and take only offline or "cold" backups, should you need to restore the database you will only be able to restore to the last backup

To enable Archivelog Mode, shutdown the database and then startup mount:

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1. SQL> shutdown immediate  
2. Database closed.  
3. Database dismounted.  
4. ORACLE instance shut down.  
5. SQL> startup mount  
6. ORACLE instance started.  
7.   
8. Total System Global Area 1068937216 bytes  
9. Fixed Size                  2233344 bytes  
10. Variable Size             763366400 bytes  
11. Database Buffers          297795584 bytes  
12. Redo Buffers                5541888 bytes  
13. Database mounted.  

Enable Archivelog Mode

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1. SQL> alter database archivelog;  
2.   
3. Database altered.  

Open the database and verify that Archivelog Mode is enabled

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1. SQL> alter database open;  
2.   
3. Database altered.  
4.   
5. SQL>  
6.   
7. SQL> SELECT LOG_MODE FROM SYS.V$DATABASE;  
8.   
9. LOG_MODE  
10. ------------  
11. ARCHIVELOG  
12.   
13. SQL>  

Step 9: Create Online Backup Script

To create automated backups, you can modify the backup.sh included under /u01/app/oracle/product/11.2.0/xe/config/scripts

Create a directory for your backup script

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1. [root@ms3 ~]# mkdir /opt/ora_backup  

Change the owner to oracle and the group to dba

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1. [root@ms3 ~]# chown oracle:dba /opt/ora_backup  

Copy the backup.sh script from /u01/app/oracle/product/11.2.0/xe/config/scripts to the directory you created above.

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1. [root@ms3 ~]# cp  /u01/app/oracle/product/11.2.0/xe/config/scripts/backup.sh /opt/ora_backup/backup.sh  

Open the backup.sh script in a text editor or vi. The last section will look like this:

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1. else  
2.    echo Backup of the database succeeded.  
3.    echo Log file is at $rman_backup_current.  
4. fi  
5.  
6. #Wait for user to press any key  
7. echo -n "Press ENTER key to exit"  
8. read userinp   

Change it to:

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1. else  
2.    echo Backup of the database succeeded.  
3.    echo Log file is at $rman_backup_current.  
4.    mail -s 'Oracle Backup Completed' 'david@davidghedini.com' < /u01/app/oracle/oxe_backup_current.log  
5. fi  
6.  
7. #Wait for user to press any key  
8. #echo -n "Press ENTER key to exit"  
9. #read userinp   

The line we added above, mail -s 'Oracle Backup Completed' 'david@davidghedini.com' < /u01/app/oracle/oxe_backup_current.log, will send us an email notification that the backup has completed as well as cat the backup log to the body of the email.

Note that we have also commented out the last two lines of the script (the prompt).

Create a cron job to run the script as user oracle.

You should run it at least once a day. With Archivelog Mode enabled, it is important that backups be taken regularly to prevent the Flash Recovery Area from filling.

Step 10: Oracle 11g XE and Application Express (APEX)

Oracle 11g Express Edition comes with Application Express 4.0.2 already installed.

If you elect to upgrade to the latest version (4.1 as of this writing), you can do so but will loose access to the XE GUI. Not a huge loss, but something to keep in mind.

Although Apex is already installed, you will need to set the Internal Admin password.

To do so, run the apxchpwd.sql located under /u01/app/oracle/product/11.2.0/xe/apex:

Note: pick something simple like Password123! as you will be prompted to change it on first log in anyways.

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1. SQL> @/u01/app/oracle/product/11.2.0/xe/apex/apxchpwd.sql  
2. Enter a value below for the password for the Application Express ADMIN user.  
3.   
4.   
5. Enter a password for the ADMIN user              []  
6.   
7. Session altered.  
8.   
9. ...changing password for ADMIN  
10.   
11. PL/SQL procedure successfully completed.  
12.   
13.   
14. Commit complete.  
15.   
16. SQL>  

You can access the Application Express GUI at:

http://localhost:8080/apex/f?p=4550:1

Replace localhost above with your IP or domain as required.

Workspace: Internal
User Name: admin
Password: (whatever you selected above).

Alternatively, you can access via

http://localhost:8080/apex/f?p=4550:10 or http://localhost:8080/apex/apex_admin

Again, replace localhost above with your IP or domain as required.

Step 11: Oracle 11g XE: Configure EPG or Apex Listener

Unless you have a license for Oracle HTTP Server (OHS), your options are the embedded PLSQL Gateway (EPG) or Apex Listener.

The Application Express that comes installed with Oracle 11g XE is configured using the EPG.

While the EPG is simpler than Apex Listener, it can be painfully slow as of Apex 3.2.

Apex Listener, while quite fast, adds an extra layer of complexity.

You will need to install an application server to run Apex Listener.

I have run Apex Listener on both Tomcat (unsupported) as well as Oracle GlassFish 3.x (supported) and was not impressed with either.

A lot of people who know far more than I do about APEX (read: 99.9999% of the population) like the Apex Listener.

Apex Listener and it's installation guide can be found here.

The Apex Listener installation guide is well done and simple to follow.

If you need to install Oracle GlassFish or GlassFish CE (basic installation is the same), you can use my GlassFish 3.1 instructions here.

If you want to be an outlaw and use Tomcat, you can use my Tomcat 6 installation guide here. or my Tomcat 7 installation guide here..