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.
[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:
[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:
[root@ms3 ~]# cd Disk1 [root@ms3 Disk1]# ls 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
[root@ms3 Disk1]# rpm -ivh oracle-xe-11.2.0-1.0.x86_64.rpm Preparing... ########################################### [100%] 1:oracle-xe ########################################### [100%] Executing post-install steps... You must run '/etc/init.d/oracle-xe configure' as the root user to configure the database. [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.
[root@ms3 Disk1]# /etc/init.d/oracle-xe configure Oracle Database 11g Express Edition Configuration ------------------------------------------------- This will configure on-boot properties of Oracle Database 11g Express Edition. The following questions will determine whether the database should be starting upon system boot, the ports it will use, and the passwords that will be used for database accounts. Press to accept the defaults. Ctrl-C will abort. Specify the HTTP port that will be used for Oracle Application Express [8080]: Specify a port that will be used for the database listener [1521]: Specify a password to be used for database accounts. Note that the same password will be used for SYS and SYSTEM. Oracle recommends the use of different passwords for each database account. This can be done after initial configuration: Confirm the password: Do you want Oracle Database 11g Express Edition to be started on boot (y/n) [y]:y Starting Oracle Net Listener...Done Configuring database...Done Starting Oracle Database 11g Express Edition instance...Done Installation completed successfully.
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
[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’:
[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:
. /u01/app/oracle/product/11.2.0/xe/bin/oracle_env.sh
You should now be able to access SQL*Plus
[root@ms3 bin]# sqlplus /nolog SQL*Plus: Release 11.2.0.2.0 Production on Wed Sep 21 08:17:26 2011 Copyright (c) 1982, 2011, Oracle. All rights reserved. SQL> connect sys/Password as sysdba Connected. 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
SQL> EXEC DBMS_XDB.SETLISTENERLOCALACCESS(FALSE); 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
SQL> show parameter DB_RECOVERY_FILE_DEST; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest string /u01/app/oracle/fast_recovery_area db_recovery_file_dest_size big integer 10G SQL>
So, to move it elsewhere, first create the new directory
[root@ms3 ~]# mkdir /opt/fra
Change the owner to oracle and the group to dba
[root@ms3 ~]# chown oracle:dba /opt/fra
Now, change the DB_RECOVERY_FILE_DEST to the location you selected above.
SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST = '/opt/fra'; System altered. SQL>
To move the files use the movelog.sql script:
SQL> @?/sqlplus/admin/movelogs SQL> SET FEEDBACK 1 SQL> SET NUMWIDTH 10 SQL> SET LINESIZE 80 SQL> SET TRIMSPOOL ON SQL> SET TAB OFF SQL> SET PAGESIZE 100 SQL> declare 2 cursor rlc is 3 select group# grp, thread# thr, bytes/1024 bytes_k 4 from v$log 5 order by 1; 6 stmt varchar2(2048); 7 swtstmt varchar2(1024) := 'alter system switch logfile'; 8 ckpstmt varchar2(1024) := 'alter system checkpoint global'; 9 begin 10 for rlcRec in rlc loop 11 stmt := 'alter database add logfile thread ' || 12 rlcRec.thr || ' size ' || 13 rlcRec.bytes_k || 'K'; 14 execute immediate stmt; 15 begin 16 stmt := 'alter database drop logfile group ' || rlcRec.grp; 17 execute immediate stmt; 18 exception 19 when others then 20 execute immediate swtstmt; 21 execute immediate ckpstmt; 22 execute immediate stmt; 23 end; 24 execute immediate swtstmt; 25 end loop; 26 end; 27 / PL/SQL procedure successfully completed. SQL> SQL>
Now, set an appropriate size for the Fast Recovery Area. Use df -h to insure that there is ample space.
SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE = 20G; System altered.
Verify the new location and size.
SQL> show parameter DB_RECOVERY_FILE_DEST; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ db_recovery_file_dest string /opt/fra db_recovery_file_dest_size big integer 20G SQL>
Step 6: Add Redo Log Members to Groups
You should have at least two Redo Log Groups and each group should have at least two members.
Additionally, the members should be spread across disks (or at least directories)
For whatever reason, only one member is created per group on install.
You can view the redo log files using SQL> SELECT * FROM V$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
SQL> ALTER DATABASE ADD LOGFILE MEMBER '/u01/app/oracle/oradata/XE/log1b.LOG' TO GROUP 1; Database altered. SQL> ALTER DATABASE ADD LOGFILE MEMBER '/u01/app/oracle/oradata/XE/log2b.LOG' TO GROUP 2; Database altered. SQL>
Step 7: Set Sessions and Processes Parameters
The default values for parameters and sessions is quite low on the default installation.
SQL> show parameters sessions; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ java_max_sessionspace_size integer 0 java_soft_sessionspace_limit integer 0 license_max_sessions integer 0 license_sessions_warning integer 0 sessions integer 172 shared_server_sessions integer SQL> show parameters processes; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ aq_tm_processes integer 0 db_writer_processes integer 1 gcs_server_processes integer 0 global_txn_processes integer 1 job_queue_processes integer 4 log_archive_max_processes integer 4 processes integer 100
You can increase these parameters.
After each change, you will need to restart the database.
Increase sessions and then bounce database.
SQL> alter system set sessions=250 scope=spfile; System altered. SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> startup ORACLE instance started. Total System Global Area 1068937216 bytes Fixed Size 2233344 bytes Variable Size 780143616 bytes Database Buffers 281018368 bytes Redo Buffers 5541888 bytes Database mounted. Database opened.
Verify change to sessions parameter:
SQL> show parameters sessions; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ java_max_sessionspace_size integer 0 java_soft_sessionspace_limit integer 0 license_max_sessions integer 0 license_sessions_warning integer 0 sessions integer 252 shared_server_sessions integer
Increase processes and restart database
SQL> alter system set processes=200 scope=spfile; System altered. SQL> Database dismounted. ORACLE instance shut down. SQL> startup ORACLE instance started. Total System Global Area 1068937216 bytes Fixed Size 2233344 bytes Variable Size 763366400 bytes Database Buffers 297795584 bytes Redo Buffers 5541888 bytes Database mounted. Database opened.
Verify change to processes parameter:
SQL> show parameters processes; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ aq_tm_processes integer 0 db_writer_processes integer 1 gcs_server_processes integer 0 global_txn_processes integer 1 job_queue_processes integer 4 log_archive_max_processes integer 4 processes integer 200 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:
SQL> shutdown immediate Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 1068937216 bytes Fixed Size 2233344 bytes Variable Size 763366400 bytes Database Buffers 297795584 bytes Redo Buffers 5541888 bytes Database mounted.
Enable Archivelog Mode
SQL> alter database archivelog; Database altered.
Open the database and verify that Archivelog Mode is enabled
SQL> alter database open; Database altered. SQL> SQL> SELECT LOG_MODE FROM SYS.V$DATABASE; LOG_MODE ------------ ARCHIVELOG 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
[root@ms3 ~]# mkdir /opt/ora_backup
Change the owner to oracle and the group to dba
[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.
[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:
else echo Backup of the database succeeded. echo Log file is at $rman_backup_current. fi #Wait for user to press any key echo -n "Press ENTER key to exit" read userinp
Change it to:
else echo Backup of the database succeeded. echo Log file is at $rman_backup_current. mail -s 'Oracle Backup Completed' 'david@davidghedini.com' < /u01/app/oracle/oxe_backup_current.log fi #Wait for user to press any key #echo -n "Press ENTER key to exit" #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.
SQL> @/u01/app/oracle/product/11.2.0/xe/apex/apxchpwd.sql Enter a value below for the password for the Application Express ADMIN user. Enter a password for the ADMIN user [] Session altered. ...changing password for ADMIN PL/SQL procedure successfully completed. Commit complete. 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..