Consideration Before Migration
- Source database version
- Oracle Database Cloud Service database version
- On-premises host operating system and version
- On-premises database character set
- Quantity of data, including indexes
- Data types used in the on-premises database
- Storage for data staging
- Acceptable length of system outage
- Network bandwidth and connectivity
- Migration Tips for Database, Run AWR to get report to determine best OCI DB offering, & Run during peak and non-peak workloads. For autonomous, use MV2ADB,All other cases, try ZDM, If neither work, use other manual methods
- Active Data Guard Included in Extreme Performance and Exadata Offloads read only, fast incremental backups
- Pre-Req for DataGuard on cloud
- VM – Standby automatically created
- BM – Standby must already exist
- Both DB systems must be in same compartment and have the same shape
- Database versions must be identical
- Port 1521 must be open and use same VCN
- Enable/Disable DataGuard on BMs and VMs
- Switchover and Failover
- Reinstate a database
RMAN [Recovery Manager]: A command-line tool used to back up database data to a storage device and restore a database from the backup.
One of the advantages of RMAN with the Oracle Database Cloud Backup Module is that it can do the backup over the internet, using secure upload to the Oracle Cloud Infrastructure Object Storage bucket, without using VPN or Oracle Cloud Infrastructure FastConnect. It is a point-in-time physical backup.
ZDM [Zero Down Time Migration] :
Oracle Zero Downtime Migration (ZDM) is the Oracle Maximum Availability Architecture (MAA)-recommended solution to migrate Oracle Databases to the Oracle Cloud. ZDM’s inherent design keeps in mind the migration process as straightforward as possible and to ensures the most negligible impact on production workloads. The source database to be migrated can be on-premises, deployed on Oracle Public Cloud Gen 1 or Oracle Cloud Infrastructure. The target database deployment can be in a Database Cloud Service on Oracle Cloud Infrastructure (OCI) Virtual Machine, Exadata Cloud Service, Exadata Cloud at Customer, or Autonomous Database. ZDM automates the entire migration process, reducing the chance of human errors. ZDM leverages Oracle Database-integrated high availability (HA) technologies such as Oracle Data Guard and GoldenGate and follows all MAA best practices that ensure no significant downtime of production environments
Data Pump :
Oracle Data Pump technology enables very high-speed movement of data and metadata from one database to another. It is a logical backup
Data Guard :
When your goal is to migrate the source database to the destination and keep the database release the same, you can use the “Simple Data Guard” solution. When your goal is to upgrade your source database to a later version in addition to migrating the source database to the target, you would use the “Advanced Data Guard” solution.
Golden Gate :
Oracle GoldenGate logical replication enables all databases in an Oracle GoldenGate configuration, both the source database and the target database, to be open read-write. Oracle GoldenGate is a key component of Oracle’s Massive Availability Architecture for addressing a broad range of high availability challenges for zero downtime maintenance, cross platform migration, and continuous data availability.Bi-directional replication can be configured from the migrated database back to the production database for use as a fallback solution
When to Use
|Expected Outage Time
|Zero to seconds
DB must support Golden Gate
|Oracle Data Guard
|Less than 5 minutes
|Suitable for exact replica [1node-1node, 2node-2node, same version -same version]
Source DB size> 2TB
|Oracle Recovery Manager
|Less than 2 hours
|Source DB Size < 2 TB,
The database is a non-CDB database, which does not use the Oracle multitenant architecture
|Instantiate from Oracle Cloud backup
|Minutes to hours, depending on database size
Data Guard vs Golden Gate
- Data Guard is an Oracle-specific technology while GoldenGate support heterogeneous database systems including all the major RDBMS as DB2,Sybase, MySQL .
- Data Guard supports active-passive replication. One of the databases is the primary database and the other one is in an inactive Data Guard mode.
- GoldenGate supports an active-active replication mode and allows both systems to work simultaneously while maintaining the data integrity.
- GoldenGate allows the transformation of the data, with conflict management while it is being replicated between both database systems.
- GoldenGate allows replication across platform. Data can be extracted from a Unix platform and replicated to an Oracle database running on platform Windows.
- GoldenGate has many case of utilization. The use of flat files for data transportation and the support of heterogeneous systems makes the technology so very interesting
Maximum Availability Architecture Best Practice
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DB Migration Best Practice
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