Data Guard
Common Creation Tasks
- Prerequisites
- Primary Database Changes
- Network Changes
- RMAN Backup and File Copy
- Standby Database Changes: OMF | ASM
- Configure Broker
- Enable Flashback Database
- Add Database to Oracle-Restart (if used)
Specs used in examples:
IP Hostname Role db_name db_unique_name ORACLE_SID (Env Var) -------------- --------- ------- -------- --------------- -------------------- 192.168.56.101 lnx01 Primary oradb oradb oradb 192.168.56.102 lnx02 Standby oradb oradb_sb oradb_sb
- SB = Standby database system.
- For RAC examples lnxsb is used for the SB host while lnx01 & lnx02 are the nodes.
Common Gotchas
- Case
Some names\passwords are now case sensitive so you may need to consider:alter system set sec_case_sensitive_logon=false scope=both;
- Creating the password file on Primary using ignorecase.
orapwd file=$ORACLE_HOME/dbs/orapwMyDB password=mypw entries=10 force=y ignorecase=y
- Check case and ownership of password file.
ls -l $ORACLE_HOME/dbs/orapw*
- Using lower case for all listener and tnsnames.ora entries.
- For 12.2\18c add sqlnet.ora entry:
SQLNET.ALLOWED_LOGON_VERSION_SERVER=11
See Case-Insensitive Passwords
- Flashback
- If Flashback Database is not enabled, you will have to manually recreate your Primary as a Standby in a failover event to reinstate it. With multi-terabyte databases common and depending on the network connectivity between your primary and standby sites, this could end up being quite a lengthy process.
- ORACLE_HOME
- For RAC & Oracle-Restart the listener.ora static service entries must be the DATABASE ORACLE_HOME. Not GRID_HOME. Example:
(ORACLE_HOME=/u01/app/oracle/product/12.1.0.2/dbhome_1)
- For RAC & Oracle-Restart the listener.ora static service entries must be the DATABASE ORACLE_HOME. Not GRID_HOME. Example:
- Password File (12c and earlier)
- If a SYSDBA account password is changed (SYS) you have to recopy the password file to the Standby. It is not replicated.
- Because of encryption changes, you might need to copy the password file from Primary rather than recreating it on the Standby.
- Patches
Don't even start to configure Data Guard unless you have applied the latest patches on both the Primary and SB. - PROFILE
The PROFILE for SYS\SYSDBA may need to be less restrictive.ALTER PROFILE default LIMIT PASSWORD_LIFE_TIME UNLIMITED;
ALTER PROFILE default LIMIT PASSWORD_REUSE_TIME UNLIMITED;
- RAM
- For 18c and later the Primary and SB OS must have at least 8gb RAM or more.
- RMAN
If the Primary is RAC and the SB is not:- You cannot use
DUPLICATE TARGET DATABASE FOR STANDBY FROM ACTIVE DATABASE;
option.
There are too many mismatches in the parameter file between the two environments.
Unless there is a way in an RMAN operation to ignore the unused RAC entries. TBD. - You can still use the standard DUPLICATE option though:
DUPLICATE TARGET DATABASE FOR STANDBY NOFILENAMECHECK;
- You cannot use