Isn't Exadata multitenant friendly ? — oracle-tech

    Forum Stats

  • 3,714,733 Users
  • 2,242,615 Discussions
  • 7,845,032 Comments

Discussions

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Isn't Exadata multitenant friendly ?

York35
York35 Member Posts: 335 Bronze Badge
edited May 2020 in Exadata

Version: Exadata X5-2 EF

RDBMS version: 12.1

Question from an Exadata newbie

My shop has an Exadata appliance which hosts two critical OLTP databases and a not so critical DWH database.

They are individual databases, not PDBs.

It was built in 2015 by Oracle ACS team. Since 12.1 already had multitenant option (CDB with multiple PDBs), why didn't Oracle ACS create these DBs as PDBs ?

York35Markus FlechtnerMagnanimous

Answers

  • Andris Perkons-Oracle
    Andris Perkons-Oracle Posts: 1,099 Employee
    edited May 2020
    Since 12.1 already had multitenant option (CDB with multiple PDBs), why didn't Oracle ACS create these DBs as PDBs ?

    Multitenant is an extra-cost option. Do you have the necessary licenses?

    Andris

    York35
  • Markus Flechtner
    Markus Flechtner Member Posts: 501 Bronze Trophy
    edited May 2020

    Hi,

    in general, Oracle Multitenant works fine on Exadata.

    And it is very difficult to judge your case from the distance.

    Some aspects come into my mind:

    1. In Oracle 12.1 some Oracle features were not compatible with the multitenant architecture. This has changed with the newer releases and since18c there are no restrictions documented in the release notes anymore (there is one exception: Oracle Streams, which has never been available in the multitenant architecture and which is desupported with Oracle 19.c

    ==> if your organisation is using one of these features, they could not switch to the container database architecture.

    2. Oracle 12.1 was the initial release of Oracle Multitenant. My personal impression is that Oracle Multitenant became "mature" (i.e. "ready for production") in Oracle 12.2

    ==> maybe the ACS consultant was cautious and did not want to setup (possibly critical) production systems with this release 1.0 of a new feature (which is - in my opinion - a reaonable argument)

    3. Don't confuse "Multitenant Architecture" and "Multitenant Option". As Andris mentioned, the Multitenant Option is an extra cost option for the Enterprise Database. Without this option, you can run a container database (i.e. a database with the "Multitenant Architecture") with a single PDB only (so called "single-tenant-option". So people say that single-tenant is a good starting point for learning the new architecture, others say that the benefits of single-tenant are relatively small, but there is an additional level of complexity because of the "dictionary split" between CDB$ROOT and PDB)

    I'm pretty sure the the ACS consultants did not decide on the architecture on their own but after a discussion these aspects (and maybe more) with your colleagues.

    HTH

    Markus

    York35
  • York35
    York35 Member Posts: 335 Bronze Badge
    edited May 2020

    Hi Andris

    Not for this deployment. But, it could be arranged if it is worth investing in.

    As I understand, in 19c, I can have up to 3 PDBs for a CDB without purchasing a multitenant licence.

  • Markus Flechtner
    Markus Flechtner Member Posts: 501 Bronze Trophy
    edited May 2020

    Hi,

    you're right: for 19c the restriction was lifted (Quote from the 19c Licensing information (https://docs.oracle.com/en/database/oracle/oracle-database/19/dblic/Licensing-Information.html#GUID-0F9EB85D-4610-4EDF-8… ): "For all offerings, if you are not licensed for Oracle Multitenant, then you may have up to 3 user-created PDBs in a given container database at any time")

    Regards

    Markus

    Magnanimous
  • Andris Perkons-Oracle
    Andris Perkons-Oracle Posts: 1,099 Employee
    edited May 2020

    You are right. 19c offers up to three PDBs without the need for additional licenses, and with 20c, you won't even have the option to install anything but a multitenant architecture.

    But the initial question was: why not then, with 12.1?

    Markus already gave some very good considerations and possible reasons. I don't know where your three databases came from (Were they migrated? Were these new installations?), but anyway - the decision to create PDBs instead of "the old model" databases, is something ACS will not make on their own.

    Markus Flechtner
Sign In or Register to comment.