Oracle Data Guard an Overview

Introduction to Oracle Data Guard

Oracle Data Guard ensures high availability, data protection, and disaster recovery for enterprise data. Oracle Data Guard maintains a transactionally consistent copy of the primary database known as physical standby database to achieve high availability, data protection, and disaster recovery.
The primary & standby databases can be either a single-instance Oracle database or an Oracle Real Application Clusters (Oracle RAC) database. A primary database can support up to 30 standby databases.
The Standby databases may be dispersed geographically and are connected by Oracle Net. The Standby databases are synchronized with the primary database using oracle log transport and redo apply services.

Types of standby database in oracle

Physical standby database: Provides a physically identical copy of the primary database, with on-disk database structures that are identical to the primary database on a block-for-block basis. Most widely used type of standby database.

Logical standby database: Contains the same logical information as the production database, although the physical organization and structure of the data can be different.

Snapshot Standby Database: The physical standby database can be temporarily converted to a snapshot standby database, Snapshot Standby Database is best used in scenarios that require a temporary,updatable snapshot of a physical standby database. The redo data received by a snapshot standby database is not applied until the snapshot standby is converted back into a physical standby database. The local changes made in snapshot standby database is discarded as soon as it is converted back to physical standby database.

Far Sync Instances: An Oracle Data Guard far sync instance is a remote Oracle Data Guard destination that accepts redo from the primary database and then ships that redo to other members of the Oracle Data Guard configuration. A far sync instance only requires initfile, password file and controlfile. It does not have any datafile. It receives redo into standby redo logs (SRLs), and archives those SRLs to local archived redo logs and then ships that redo to other members of the Oracle Data Guard configuration
NOTE: Far sync instances are part of the Oracle Active Data Guard Far Sync feature, which requires an Oracle Active Data Guard license.

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DataPump Import Of Object Types Fails With Errors ORA-39083 ORA-2304 Or ORA-39117 ORA-39779

<<Back to Oracle DATAPUMP Main Page ORA-39083: Object type TYPE:"TEST_QA01"."LOG_RECORD" failed to create with error: ORA-02304: invalid object identifier literal Import: Release 12.1.0.2.0 - Production on Tue May 29 07:59:12 2018 Copyright (c) 1982, 2014, Oracle and/or its affiliates. All rights reserved. Connected to: Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production With the Partitioning, Real Application Clusters, Automatic Storage Management, Oracle Label Security, OLAP, Advanced Analytics and Real Application Testing options Master table "SYSTEM"."SYS_IMPORT_FULL_01" successfully loaded/unloaded Starting "SYSTEM"."SYS_IMPORT_FULL_01": system/********@TEST_QA parfile=import_TEST.par Processing object type SCHEMA_EXPORT/USER Processing object type SCHEMA_EXPORT/SYSTEM_GRANT Processing object type SCHEMA_EXPORT/ROLE_GRANT Processing object type SCHEMA_EXPORT/DEFAULT_ROLE Pr

ORA-28374: typed master key not found in wallet

<<Back to Oracle DB Security Main Page ORA-46665: master keys not activated for all PDBs during REKEY SQL> ADMINISTER KEY MANAGEMENT SET KEY FORCE KEYSTORE IDENTIFIED BY xxxx WITH BACKUP CONTAINER = ALL ; ADMINISTER KEY MANAGEMENT SET KEY FORCE KEYSTORE IDENTIFIED BY xxxx WITH BACKUP CONTAINER = ALL * ERROR at line 1: ORA-46665: master keys not activated for all PDBs during REKEY I found following in the trace file REKEY: Create Key in PDB 3 resulted in error 46658 *** 2019-02-06T15:27:04.667485+01:00 (CDB$ROOT(1)) REKEY: Activation of Key AdnU5OzNP08Qv1mIyXhP/64AAAAAAAAAAAAAAAAAAAAAAAAAAAAA in PDB 3 resulted in error 28374 REKEY: Keystore needs to be restored from the REKEY backup.Aborting REKEY! Cause: All this hassle started because I accidently deleted the wallet and all wallet backup files too and also forgot the keystore password. There was no way to restore the wallet back. Fortunately in my case the PDB which had encrypted data was supposed to be deco

How to Find VIP of an Oracle RAC Cluster

<<Back to Oracle RAC Main Page How to Find Out VIP of an Oracle RAC Cluster Login clusterware owner (oracle) and execute the below command to find out the VIP hostname used in Oracle RAC $ olsnodes -i node1 node1-vip node2 node2-vip OR $ srvctl config nodeapps -viponly Network 1 exists Subnet IPv4: 10.0.0.0/255.255.0.0/bondeth0, static Subnet IPv6: Ping Targets: Network is enabled Network is individually enabled on nodes: Network is individually disabled on nodes: VIP exists: network number 1, hosting node node1 VIP Name: node1-vip VIP IPv4 Address: 10.0.0.1 VIP IPv6 Address: VIP is enabled. VIP is individually enabled on nodes: VIP is individually disabled on nodes: VIP exists: network number 1, hosting node node2 VIP Name: node2-vip VIP IPv4 Address: 10.0.0.2 VIP IPv6 Address: VIP is enabled. VIP is individually enabled on nodes: VIP is individually disabled on nodes:

How to Power On/off Oracle Exadata Machine

<<Back to Exadata Main Page How to Power On/off Oracle Exadata Machine Oracle Exadata machines can be powered on/off either by pressing the power button on front of the server or by logging in to the ILOM interface. Powering on servers using button on front of the server The power on sequence is as follows. 1. Start Rack, including switches Note:- Ensure the switches have had power applied for a few minutes to complete power on configuration before starting Exadata Storage Servers 2.Start Exadata Storage Servers Note:- Ensure all Exadata Storage Servers complete the boot process before starting the database servers 3. Start Database Servers Powering On Servers Remotely using ILOM The ILOM can be accessed using the Web console, the command-line interface (CLI), IPMI, or SNMP. For example, to apply power to server dm01cel01 using IPMI, where dm01cel01-ilom is the host name of the ILOM for the server to be powered on, run the

How to Attach to a Datapump Job and Check Status of Export or Import

<<Back to Oracle DATAPUMP Main Page How to check the progress of export or import Jobs You can attach to the export/import job using ATTACH parameter of oracle datapump utility. Once you are attached to the job you check its status by typing STATUS command. Let us see how Step1> Find the Export/Import Job Name You can find the datapump job information from DBA_DATAPUMP_JOBS or USER_DATAPUMP_JOBS view. SQL> SELECT OWNER_NAME,JOB_NAME,OPERATION,JOB_MODE,STATE from DBA_DATAPUMP_JOBS; OWNER_NAME JOB_NAME OPERATION JOB_MODE STATE ---------- ------------------------------ -------------------- ---------- ---------- SYSTEM SYS_EXPORT_FULL_02 EXPORT FULL EXECUTING OR You can also find the job name for export/import in logfile in beginning itself. Step2>Attach to the Job and check status One you get the Export/Import Job Name attach the job and check its status. You can attach or det

How to Create Pfile from Spfile and Vice Versa

<<Back to DB Administration Main Page There are instances when a DBA need to start the database using pfile, for example to trouble an instance startup error or to validate init file post parameter changes etc. In such situations you can create a pfile from spfile and once you are done with your changes you can create spfile from updated/modified pfile to start the database. How to Create Pfile from Spfile As sysdba execute following command SQL> create pfile='/tmp/initOrcl.ora' from spfile; How to Create SPfile from Pfile As sysdba execute following command SQL> create spfile from pfile='/tmp/initOrcl.ora'; You can also create the pfile directly from memory How to Create Pfile from Memory As sysdba execute following command SQL> create pfile='/tmp/initOrcl.ora' from memory;

How to export only data or only metadata using expdp

<<Back to Oracle DATAPUMP Main Page CONTENT parameter of expdp let you select whether you want to export only data or only metadata or both Default : ALL Syntax and Description CONTENT=[ALL | DATA_ONLY | METADATA_ONLY] DATA_ONLY exports only table row data; no database object definitions are exported. METADATA_ONLY exports only database object definitions; no table row data is exported. Exporting metadata only $ cat exp_full_pdb01.par directory=dump dumpfile=EXP_PDB01_FULL%U.dmp logfile=EXP_PDB01_FULL.log full=y CONTENT=METADATA_ONLY $ expdp system@PDB01 parfile=exp_full_pdb01.par Exporting data only directory=dump dumpfile=EXP_PDB01_FULL%U.dmp logfile=EXP_PDB01_FULL.log full=y CONTENT=DATA_ONLY $ expdp system@PDB01 parfile=exp_full_pdb01.par

Step by Step How to Configure Software Keystore/ Oracle Wallet

<<Back to Oracle DB Security Main Page How to Configure a Software Keystore A software keystore is a container that stores the Transparent Data Encryption master encryption key. To configure a software Keystore follow the steps below. Step 1: Set the Keystore Location in the sqlnet.ora File You can store the software keystore (also known as wallet) in file system or in ASM Diskgroup. Does not matter where you want to store the keystore you have modify the sqlnet.ora and make an entry accordingly Make an entry as shown below in $ORACLE_HOME/network/admin/sqlnet.ora file Example1: If Storing the Wallet in ASM ENCRYPTION_WALLET_LOCATION= (SOURCE=(METHOD=FILE) (METHOD_DATA= (DIRECTORY= +DG_TST_DATA/$ORACLE_SID/wallet ) ) ) Example2: If Storing the Wallet in File System ENCRYPTION_WALLET_LOCATION= (SOURCE=(METHOD=FILE) (METHOD_DATA= (DIRECTORY= /u01/dbatst1/admin/wallet/$ORACLE_SID) ) ) NOTE: Ensure that the path you entered in DIREC

ORA-15040: diskgroup is incomplete

<<Back to Oracle ASM Main Page ORA-15040: diskgroup is incomplete SQL> startup ORA-00099: warning: no parameter file specified for ASM instance ASM instance started Total System Global Area 1140850688 bytes Fixed Size 8629704 bytes Variable Size 1107055160 bytes ASM Cache 25165824 bytes ORA-15110: no diskgroups mounted Reason: The reason of this error is simply the ASM is not able to find the some or all the disks. Solution: Investigate and make all the disks available to ASM to mount the disk group. Make sure the disks has proper permissions. If you are using AFD check following services are online oracleacfs oracleadvm oracleoks oracleafd Source of Problem : Issue started after restart of the server After restarting the server when I tried to start the ASM instance its started throwing error. ORA-15110: no diskgroups mounted Investigation in my Case Step1> ASM Logfile Scanning Looked i

ORA-28365: wallet is not open while starting the database

<<Back to DB Administration Main Page ORA-28365: wallet is not open Encountered while Starting the Database $ srvctl start instance -d CDB001 -i CDB0011 PRCR-1013 : Failed to start resource ora.cdb001.db PRCR-1064 : Failed to start resource ora.cdb001.db on node node1.oracle.com CRS-5017: The resource action "ora.cdb001.db start" encountered the following error: ORA-28365: wallet is not open . For details refer to "(:CLSN00107:)" in "/u01/app/oracle/diag/crs/node1.oracle.com/crs/trace/crsd_oraagent_oracle.trc". CRS-2674: Start of 'ora.cdb001.db' on 'node1.oracle.com' failed Solution : Start the instance in mount mode SQL> startup mount; ORACLE instance started. Total System Global Area 2147483648 bytes Fixed Size 2926472 bytes Variable Size 1392511096 bytes Database Buffers 738197504 bytes Redo Buffers 13848576 bytes Database mounted. Check Wallet status set linesiz

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