# Setup Oracle Data Guard observer This is the first time in several years that I've configured a DataGuard observer. See in the following how to install and configure Oracle Dataguard observer for Oracle database 19c (on Exadata @ OCI /ODB@AWS, should work similaron other envs making a difference just to be transparent here) Software installation has been done by my favorite tool: autoupgrade :-) ## preps ### install oracle preinstall download the preinstall from public yum repo ```bash wget https://yum.oracle.com/repo/OracleLinux/OL8/appstream/x86_64/getPackage/oracle-database-preinstall-19c-1.0-4.el8.x86_64.rpm ``` install with ```bash sudo dnf localinstall oracle-database-preinstall-19c-1.0-4.el8.x86_64.rpm ``` I've faced an issue with the preinstalled bindutils version on my EC2 instance. I was not able to tell yum or dnf to omit the package with ```--no-best``` therefore I removed the bindutils manually with ``` sudo yum remove bind9.16-utils.x86_64 ``` and was able to install oracle preinstall 19c package afterwards ### install java & zip autoupgrade needs an installed java and zip cli. ```bash yum install zip -y yum install java -y ``` ### autoupgrade etc as we now have an oracle user we could switch to the oracle user and do our work with that user ```bash mkdir autoupgrade ``` download autoupgrade ```bash wget https://download.oracle.com/otn-pub/otn_software/autoupgrade.jar ``` create a config file for autoupgrade to download the software I've used autoupgrade composer by Marcus Vinicius to ease the config file creation. ``` bash touch download-19c.cfg ``` add the following (adapt if needed) ```ìni # Created by AutoUpgrade Composer # AutoUpgrade Version: 26.6 # Patch, ExecMode: Download global.global_log_dir=/home/oracle/autoupgrade/log global.keystore=/home/oracle/autoupgrade/keystore patch1.log_dir=/home/oracle/autoupgrade/log/patch1 patch1.download_folder=/home/oracle/autoupgrade/patches patch1.patch=RU patch1.target_version=19 patch1.platform=LINUX.X64 ``` now we're nearly ready to download the patches first load the password to the keystore , for details see my other blog around autoupgrade ```bash java -jar autoupgrade.jar -config download-19c.cfg -patch -load_password ``` let's download the patches: ```bash java -jar autoupgrade.jar -config download-19c.cfg -patch -mode download ``` ``` java -jar autoupgrade.jar -config download-19c.cfg -patch -mode download AutoUpgrade Patching 26.6.260925 launched with default internal options Processing config file ... Loading AutoUpgrade Patching keystore AutoUpgrade Patching keystore is loaded AutoUpgrade Patching adds the MRP and OCW options to the PATCH configuration parameter because the generated Gold Image always includes those fixes. Connected to Oracle Update Advisor service |- Requesting Gold Images AutoUpgrade Patching has finished processing the Gold Image requests ----------------------------------------------------- Downloading files to /home/oracle/autoupgrade/patches ----------------------------------------------------- DB Gold Image - 19.33.0.0.0 File: db_goldimage_19_33_20261103131316.zip - VALIDATED ----------------------------------------------------- ``` let's go ahead and install the database home create a new autoupgrade config ``` vi install-19c.cfg ``` add the following ```ini # Created by AutoUpgrade Composer # AutoUpgrade Version: 26.6 # Patch, ExecMode: CreateHome global.global_log_dir=/home/oracle/autoupgrade/log patch1.log_dir=/home/oracle/autoupgrade/log/DB1 patch1.download_folder=/home/oracle/autoupgrade/patches patch1.patch=RU patch1.target_version=19 patch1.target_home=/u00/app/oracle/product/%RELEASE%.%UPDATE%/dbhome_1 patch1.home_settings.edition=ee patch1.home_settings.oracle_base=/u00/app/oracle patch1.home_settings.inventory_location=/u00/app/oraInventory ``` ```bash java -jar autoupgrade.jar -config install-19.cfg -patch -mode create_home ``` ## the dataguard observer part ### preps create a small env file to have all the needed env vars set automatically ```bash cat ora.env export ORACLE_HOME=/u00/app/oracle/product/19.33/dbhome_1/ export ORACLE_BASE=/u00/app/oracle/ export PATH=$PATH:$ORACLE_HOME/bin export TNS_ADMIN=$ORACLE_HOME/network/admin ``` ### networking & db connectivity configure tnsnames for primary and standby database ```ìni DG_SITE1 = (DESCRIPTION = (CONNECT_TIMEOUT = 120) (RETRY_COUNT = 3) (TRANSPORT_CONNECT_TIMEOUT = 90) (ADDRESS_LIST = (LOAD_BALANCE = yes) (ADDRESS = (PROTOCOL = TCP)(HOST = vmc-prd-01-scan.client.wjad0tl.oraclevcn.com)(PORT = 1521)) ) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = demo_site1.client.demo1.oraclevcn.com) (UR = A) (FAILOVER_MODE = (TYPE = select)(METHOD = basic)) ) ) DG_SITE2 = (DESCRIPTION = (CONNECT_TIMEOUT = 120) (RETRY_COUNT = 3) (TRANSPORT_CONNECT_TIMEOUT = 90) (ADDRESS_LIST = (LOAD_BALANCE = yes) (ADDRESS = (PROTOCOL = TCP)(HOST = vnc-stby-01-scan.client.demo2.oraclevcn.com(PORT = 1521)) ) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = demo_site2.client.demo2.oraclevcn.com)) (UR = A) (FAILOVER_MODE = (TYPE = select)(METHOD = basic)) ) ) ``` tnsping to both sites above should be fine ```bash Used TNSNAMES adapter to resolve the alias Attempting to contact (DESCRIPTION = (CONNECT_TIMEOUT = 120) (RETRY_COUNT = 3) (TRANSPORT_CONNECT_TIMEOUT = 90) (ADDRESS_LIST = (LOAD_BALANCE = yes) (ADDRESS = (PROTOCOL = TCP)(HOST = vmc-prd-01-scan.client.wjad0tl.oraclevcn.com))(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = demo_site1.client.demo1.oraclevcn.com (UR = A) (FAILOVER_MODE = (TYPE = select)(METHOD = basic)))) OK (0 msec) ``` #### wallet config as we're running on 19c observer includes the option to run in background. to achieve that we need to ensure passwordless authentication to the database is possible. add the following to our sqlnet.ora ```bash vi $TNS_ADMIN/sqlnet.ora WALLET_LOCATION = (SOURCE = (METHOD = FILE) (METHOD_DATA = (DIRECTORY = /u00/app/oracle/admin/wallet)) ) SQLNET.WALLET_OVERRIDE = TRUE ``` create the wallet dir if it does not exist ```bash mkdir /u00/app/oracle/admin/wallet ``` initialize a wallet (provide a password when prompted) ```bash mkstore -wrl /u00/app/oracle/admin/wallet -create ``` store the passwords ```bash mkstore -wrl /u00/app/oracle/admin/wallet -createCredential DG_SITE1 sys mkstore -wrl /u00/app/oracle/admin/wallet -createCredential DG_SITE2 sys ``` mkstore -wrl /u00/app/oracle/admin/wallet -listCredential test the connection ```bash sqlplus /@DG_SITE1 as sysdba sqlplus /@DG_SITE2 as sysdba ``` should be successful without a password prompt ### observer config create a directory to hold the configs mkdir /u00/app/oracle/admin/fsfo ```bash dgmgrl connect /@dg_site1; show configuration enable fast_start failover; Enabled in Potential Data Loss Mode. ``` now start the observer with (also in dgmrl) ```bash start observer observer1 in background file is '/u00/app/oracle/admin/fsfoobserver1_dg.dat' logfile is '/u00/app/oracle/admin/fsfo/observer1.log' connect identifier is dg_site1; ``` output will look like ``` [...] Submitted command "START OBSERVER" using connect identifier "DG_SITE1" DGMGRL> DGMGRL for Linux: Release 19.0.0.0.0 - Production on Wed Nov 4 10:35:35 2026 Version 19.33.0.0.0 Copyright (c) 1982, 2019, Oracle and/or its affiliates. All rights reserved. [...] Connected as SYSDBA. Observer file "/u00/app/oracle/admin/fsfoobserver1_dg.dat" is created. Succeeded in opening the observer file "/u00/app/oracle/admin/fsfoobserver1_dg.dat". [W000 2026-11-04T10:35:38.522+00:00] FSFO target standby is DG_SITE2 Observer 'i-xxxx.eu-central-1.compute.internal1' started The observer log file is '/u00/app/oracle/admin/fsfo/observer_dg1.log'. ``` Check the configuration (with dgmgrl) ``` show configuration [...] Fast-Start Failover: Enabled in Potential Data Loss Mode Lag Limit: 30 seconds Lag Type: APPLY Threshold: 30 seconds Active Target: DG_SITE2 Potential Targets: "DG_SITE2" DG_SITE2 valid Observer: i-xxx.eu-central-1.compute.internal1 Shutdown Primary: TRUE Auto-reinstate: TRUE Observer Reconnect: (none) Observer Override: FALSE Lag Grace Time: 0 seconds ``` That's it :-) We've succesfully installed and configured DataGuard observer with the help of autoupgrade. ### summary/lessons learned - autoupgrade eases and helps here as well by installing the needed oracle home - make use of autoupgrade composer to get the needed config files created - create wallets for the db credentials to keep observer running in background ### Links, further reading DataGuard docs and best practices * https://docs.oracle.com/en/database/oracle/oracle-database/19/dgbkr/using-data-guard-broker-to-manage-switchovers-failovers.html?source=%3Aso%3Ach%3Aor%3Aawr%3A%3A%3A%3APrivateEndpointsPlaybook&utm_source=chatgpt.com * https://docs.oracle.com/en/database/oracle/oracle-database/19/sbydb/introduction-to-oracle-data-guard-concepts.html * https://docs.oracle.com/en/database/oracle/oracle-database/19/haovw/oracle-data-guard.html Ludovicos blog around DataGuard and Oracle Database * https://www.ludovicocaldara.net/ Guide to Oracle Data Guard Fast-Start Failover * https://www.oracle.com/technical-resources/articles/smiley-fsfo.html autoupgrade composer by Marcus Vinicius * https://viniciusdba.com.br/autoupgrade-composer/ step by step doc for FSFP by Google Cloud * https://docs.cloud.google.com/oracle/compute/gcnv-configure-broker-fsfo-observer