Active - Active or 2-way replication is very similar to 1-way replication. This is used when changes can be made to both databases and they both must be kept in sync.
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2-way replication can be configured through the setup wizard.
To configure 2-way replication, two replication pairs have to be setup. The default in the setup wizard is to configure only 1 pair.
This example show an Oracle-to-Oracle two-way replication using the following information.
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Click here for prerequisite checklist. |
| Server/Database | Name |
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| Source database | reptest1 |
| Source server | dbvldemo101 |
| Target database | reptest2 |
| Target server | dbvldemo102 |
| TNS alias for source database: | reptest1 |
| TNS alias for target database | reptest2 |
Throughout the wizard, defaults are shown in [brackets]. Just press enter to accept them. The replication name in this example is "reptest1".
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Enter number of replication pair to modify it, or "add", or "done": [done] add Let's configure the replication pair, selecting source and target. Following databases are described: 1: reptest1 (Oracle) 2: reptest2 (Oracle) Select source database: [1] 2 Select target database: [2] 1 (NETWORK_QUALITY) - Please specify your network type (LAN or WAN). Autoconfigures timeouts, use of compression etc. [LAN] Lock and copy the data initially one-by-one or at a single SCN? (one-by-one/single-scn/ddl-only/resetlogs) [single-scn] What data copy script to create? (dp_networklink/dp_exp/exp/ddl_file/ddl_run/none) [dp_networklink] Following replication pairs are now configured: 1: reptest1 (Oracle) ==> reptest2 (Oracle), DDL: no, fetcher: no, process suffix: (no suffix), network: LAN, prepare type: single-scn, data load: dp_networklink 2: reptest2 (Oracle) ==> reptest1 (Oracle), DDL: no, fetcher: no, process suffix: 1, network: LAN, prepare type: single-scn, data load: dp_networklink Enter number of replication pair to modify it, or "add", or "done": [done] |
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Two replication pairs are now configured.
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oracle@dbvldemo101[/home/oracle/reptest1]: ./reptest1-all.sh Setting up Dbvisit Replicate configuration Configure database reptest1... This check fails if the DBID is not the expected one... Ok, check passed. Configure database reptest2... This check fails if the DBID is not the expected one... Ok, check passed. Object grants for database reptest1... Object grants for database reptest2... Setting up the configuration Initializing......done WARN-1850: No DDC DB available, dictionary table does not exist. DDC loaded from database (0 variables). Dbvisit Replicate version 2.4.31.3038 Copyright (C) Dbvisit Software Limited. All rights reserved. DDC file /home/oracle/reptest1/reptest1-onetime.ddc loaded. MINE: Cannot determine Dbvisit Replicate dictionary version. (no dictionary exists) APPLY: Cannot determine Dbvisit Replicate dictionary version. (no dictionary exists) dbvrep> set ON_WARNING SKIP Variable ON_WARNING set to SKIP for process *. dbvrep> set ON_ERROR EXIT Variable ON_ERROR set to EXIT for process *. dbvrep> ENGINE SWITCH_REDOLOG dbvrep> ENGINE SETUP MINE DROP DICTIONARY 0 dictionary objects dropped. dbvrep> ENGINE SETUP MINE CREATE DICTIONARY dbvrep> ENGINE SETUP MINE LOAD DICTIONARY Supplemental logging on database set. Loading dictionary table DBRSCOL$ Loading dictionary table DBRSIND$ Loading dictionary table DBRSOBJ$ Loading dictionary table DBRSTAB$ Loading dictionary table DBRSUSER$ Loading dictionary table DBRSV_$DATABASE dbvrep> ENGINE SETUP APPLY DROP DICTIONARY 0 dictionary objects dropped. dbvrep> ENGINE SETUP APPLY CREATE DICTIONARY dbvrep> ENGINE SETUP APPLY LOAD DICTIONARY dbvrep> ENGINE PREPARE_DP SETUP CLEAR dbvrep> ENGINE SETUP PAIR MINE AND APPLY ID of mine proces is F8908CFE-F408-11E2-ABE7-37F589F7C5BA. If not using DDC in database, set MINE_UNIQUE_ID to this value. 1 applier SCN set. dbvrep> SET APPLY.INSTANTIATE_SCN NOW Variable INSTANTIATE_SCN set to NOW for process APPLY. dbvrep> ENGINE SUPPLEMENTAL LOGGING SCHEMA TEST1 ENABLE PRIMARY KEY dbvrep> ENGINE SUPPLEMENTAL LOGGING TABLE AVI.EMP ENABLE PRIMARY KEY dbvrep> ENGINE SWITCH_REDOLOG dbvrep> ENGINE WAIT_SCN_FLIP Waited 3 seconds until scn_to_timestamp changed. dbvrep> #single-scn instantiation: lock all tables and schemas dbvrep> ENGINE LOCK TABLES AVI.EMP Locking all tables. Lock done. dbvrep> ENGINE LOCK SCHEMAS TEST1 Locking all schemas. Lock done. dbvrep> #single-scn instantiation: unlock all tables and schemas, but keep the SCN dbvrep> ENGINE LOCK RELEASE LOCKS dbvrep> dbvrep> #prepare the tables (we use OFFLINE as neither MINE not APPLY is running; with OFFLINE we won't wait on network timeout) dbvrep> PREPARE OFFLINE SCHEMA TEST1 Table TEST1.DEPT instantiated at SCN 7849244 Table TEST1.EMP instantiated at SCN 7849244 dbvrep> PREPARE OFFLINE TABLE AVI.EMP Table AVI.EMP instantiated at SCN 7849244 dbvrep> #single-scn instantiation: unlock all tables and schemas, forget the SCN (so it does not affect any further PREPARE statements) dbvrep> ENGINE LOCK CLEAR SCN dbvrep> ENGINE SWITCH_REDOLOG dbvrep> #prepare script for instantiation dbvrep> ENGINE PREPARE_DP WRITE DP_NETWORKLINK DIRECTORY DATA_PUMP_DIR FILE /home/oracle/reptest1/APPLY.sh DBLINK reptest1 USERID SYSTEM/odb10g@reptest2 Created Data Pump script /home/oracle/reptest1/APPLY.sh, using network import. dbvrep> dbvrep> # Configuring non-default processes dbvrep> choose process MINE1 Process type MINE set to: MINE1. dbvrep> choose process APPLY1 Process type APPLY set to: APPLY1. dbvrep> ENGINE SWITCH_REDOLOG dbvrep> ENGINE SETUP MINE LOAD DICTIONARY Supplemental logging on database set. Loading dictionary table DBRSCOL$ Loading dictionary table DBRSIND$ Loading dictionary table DBRSOBJ$ Loading dictionary table DBRSTAB$ Loading dictionary table DBRSUSER$ Loading dictionary table DBRSV_$DATABASE dbvrep> ENGINE SETUP APPLY LOAD DICTIONARY dbvrep> ENGINE PREPARE_DP SETUP CLEAR dbvrep> ENGINE SETUP PAIR MINE AND APPLY ID of mine proces is 0695067C-F409-11E2-ABE7-37F589F7C5BA. If not using DDC in database, set MINE_UNIQUE_ID to this value. 1 applier SCN set. dbvrep> SET APPLY1.INSTANTIATE_SCN NOW Variable INSTANTIATE_SCN set to NOW for process APPLY1. dbvrep> ENGINE SUPPLEMENTAL LOGGING SCHEMA TEST1 ENABLE PRIMARY KEY dbvrep> ENGINE SUPPLEMENTAL LOGGING TABLE AVI.EMP ENABLE PRIMARY KEY dbvrep> ENGINE SWITCH_REDOLOG dbvrep> ENGINE WAIT_SCN_FLIP Waited 2 seconds until scn_to_timestamp changed. dbvrep> #single-scn instantiation: lock all tables and schemas dbvrep> ENGINE LOCK TABLES AVI.EMP Locking all tables. Lock done. dbvrep> ENGINE LOCK SCHEMAS TEST1 Locking all schemas. Lock done. dbvrep> #single-scn instantiation: unlock all tables and schemas, but keep the SCN dbvrep> ENGINE LOCK RELEASE LOCKS dbvrep> dbvrep> #prepare the tables (we use OFFLINE as neither MINE not APPLY is running; with OFFLINE we won't wait on network timeout) dbvrep> PREPARE OFFLINE SCHEMA TEST1 Table TEST1.DEPT instantiated at SCN 7830009 Table TEST1.EMP instantiated at SCN 7830009 dbvrep> PREPARE OFFLINE TABLE AVI.EMP Table AVI.EMP instantiated at SCN 7830009 dbvrep> #single-scn instantiation: unlock all tables and schemas, forget the SCN (so it does not affect any further PREPARE statements) dbvrep> ENGINE LOCK CLEAR SCN dbvrep> ENGINE SWITCH_REDOLOG dbvrep> #prepare script for instantiation dbvrep> ENGINE PREPARE_DP WRITE DP_NETWORKLINK DIRECTORY DATA_PUMP_DIR FILE /home/oracle/reptest1/APPLY1.sh DBLINK reptest2 USERID SYSTEM/odb10g@reptest1 Created Data Pump script /home/oracle/reptest1/APPLY1.sh, using network import. dbvrep> create ddcdb from ddcfile DDC loaded into database (291 variables). dbvrep> set ON_WARNING SKIP Variable ON_WARNING set to SKIP for process *. dbvrep> set ON_ERROR SKIP Variable ON_ERROR set to SKIP for process *. OK-0: Completed, but some operation(s) raised warnings and/or errors. These steps are required after the reptest1-all.sh script runs: 1) Create the necessary directory(ies) on the servers: dbvldemo102: /home/oracle/reptest1 2) Copy the DDC files to the server(s) where the processes will run: dbvldemo102: /home/oracle/reptest1/reptest1-APPLY.ddc dbvldemo101: /home/oracle/reptest1/reptest1-APPLY1.ddc dbvldemo101: /home/oracle/reptest1/reptest1-MINE.ddc dbvldemo102: /home/oracle/reptest1/reptest1-MINE1.ddc 3) Review that path to dbvrep executable is correct in the run scripts: /home/oracle/reptest1/reptest1-run-dbvldemo101.sh /home/oracle/reptest1/reptest1-run-dbvldemo102.sh 4) Copy the run script to the server(s) where the processes will run: /home/oracle/reptest1/reptest1-run-dbvldemo101.sh /home/oracle/reptest1/reptest1-run-dbvldemo102.sh 5) Ensure firewall is open for listen interfaces 0.0.0.0:7902, 0.0.0.0:7904, 0.0.0.0:7901, 0.0.0.0:7903 used by the processes. 6) Make sure the data on apply are in sync as of time when setup was run. Scripts for Data Pump/export/DDL were created as requested: /home/oracle/reptest1/APPLY.sh /home/oracle/reptest1/APPLY1.sh Create referenced database links (if any) before running the scripts. 7) Start the replication processes on all servers: /home/oracle/reptest1/reptest1-run-dbvldemo101.sh /home/oracle/reptest1/reptest1-run-dbvldemo102.sh 8) Start the console to monitor the progress: /home/oracle/reptest1/start-console.sh The above list is stored in /home/oracle/reptest1/Nextsteps.txt. |
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Each run script ( reptest1-run-dbvldemo101.sh and reptest1-run-dbvldemo102.sh) has commands to start both a Mine and Apply on each server.
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With 2-way replication the table listing in the console can so long that the prompt cannot be seen. By default, 30 tables are listed for each replication, thus for a 2-way replication, it takes up to 70 screen lines.
To change this, edit the *-MINE.ddc file and add line "set STATUS_BAR_ACTIVE_TABLES 5". Or enter this command at the console prompt. Restart the console for this change to take affect.