Saturday, September 28, 2013

12c data isolation for redologs and archivelogs with multiple PDBs

With 12c new functionality , You can have multiple pluggable databases (PDBs) under one container database (CDB). 
The real advantage of this compared to multiple databases on a server is 
1) more resource optimization and
2) better manageability and monitoring.

However, one of the questions that comes up is,  if PDBs all share  common online redolog files and archivelog files,  the archive logs could contain data from other PDBs and that is a potential for SLA conflict. 
PDB data is isolated at database level and can manage individual backup and recovery at PDB level. Some financial customers SLA will require that no files should share data from one company with another ? 
This may not be a issue for in-house server hosting multiple databases for a single client. but if it is a hosting service  and they can share or give archivelog to customers, this is certainly a cause for concern ?

Solution: There is a simple solution for this. It is service/PDB isolation in a RAC environment.
PDBs can run in a RAC environment. In addition, each PDB starts with a default service. This default services is available on all nodes. You can simply isolate the PDB service to one or more instance and ensure no other Oracle PDBs services run on that node. This way you can ensure that the online redologs and archive log files will  only have data for PDBs allowed to run on that node.

Services functionality in the database has been around quiet some time. We can now put them to use for data isolation in addition to load balancing and monitoring functionality they provide.

In the above diagram, you can be sure that the online redologs of ERP is available only one node.

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