DB Notes

Oracle 19c Data Guard – Standby Creation, Switchover & Failover Oracle 19c Physical Standby Creation & Management (RMAN Duplicate + Data Guard Broker) This article walks through building a physical standby using RMAN  DUPLICATE FROM ACTIVE DATABASE , then managing switchover / failover with the Data Guard Broker. The commands were tested on Oracle Linux 8 with Oracle Database 19c . Assumptions Two hosts ( oracle1.localdomain & oracle2.localdomain ) with Oracle 19c installed. Primary instance runs on oracle1 ; standby will be created on oracle2 . Listener port 1521 is reachable in both directions (check firewalls). Primary DB name MYDBPROD ; standby unique name MYDBDG . 1 – Primary Server Preparation 1.1 Switch to ARCHIVELOG & Force Logging -- Check mode SELECT log_mode FROM v$database; -- If NOARCHIVELOG: SHUTDOWN IMMEDIATE; STARTUP MOUNT; ALTER DATABASE ARCH...

Cloning MYDBPROD → MYDBTEST with RMAN DUPLICATE Sometimes we need a quick, up‑to‑date copy of production for troubleshooting or functional testing. The fastest route is RMAN duplicate from active database , which streams the data files over the network—no backup & restore cycle required. Environment snapshot oracle1 → production server (SID MYDBPROD ) oracle2 → test server (SID MYDBTEST ) Database names: MYDBP (prod) → MYDBT (test) OS: Oracle Linux 8 SELinux Permissive , firewalld disabled. Only the Oracle binaries are installed on the test host—no database. 1  Configure the listener on the test server LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = oracle2.localdomain)(PORT = 1521)) ) ) SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (ORACLE_HOME = /u01/app/oracle/product/19.0.0/dbhome_1) (SID_NAME = MYDBTEST) ) ) Start (or reload) it: lsnrctl start listener 2  Add tnsnames.ora en...

Practical RMAN Restore Guide Practical RMAN Restore Guide This guide shows how to restore and relocate an Oracle database via RMAN. We’ll assume you want all datafiles in a new folder ( /newpath instead of /oldpath ), and possibly handle redo logs in a new location as well. Steps include restoring SPFILE, cataloging backups, restoring archived logs, and point-in-time recovery. 1. Copy RMAN Backups to the New Server mkdir -p /u01/backup/test_restore cp /oldserver/backups/*.bkp /u01/backup/test_restore Copy all backup pieces (datafiles, control file, SPFILE, archivelogs) to a directory the new server can access. 2. Create Required Oracle Directories mkdir -p /u01/app/oracle/admin/MYDB/adump mkdir -p /u01/app/oracle/oradata/MYDB mkdir -p /u01/app/oracle/fast_recovery_area/MYDB mkdir -p /newpath/onlinelog Ensure directories exist for diagnostic files ( adump ), datafiles, FRA, and redo logs before proceeding. 3. Startu...

The following steps can be used to quickly reconfigure a corrupted standby database in Oracle Data Guard. These steps assume the configurations are already in place, and the commands below should be executed on the standby server. 1. Create a PFILE Create a PFILE from the current SPFILE: create pfile='/tmp/pfile.ora' from spfile; 2. Drop the Old Standby Database Use RMAN to drop the old standby database: RMAN> startup mount; RMAN> sql 'alter system enable restricted session'; RMAN> drop database including backups noprompt; 3. Create SPFILE from the PFILE After dropping the database, recreate the SPFILE from the previously created PFILE: sqlplus / as sysdba create spfile from pfile='/tmp/pfile.ora'; startup nomount; 4. Start Database Recovery Use RMAN to duplicate the database for standby: rman target sys@DWHPRI auxiliary sys@DWHDG duplicate target database for standby from active database dorecover nofilenamecheck; 5. Manage S...