Multitenant Part 1 : Overview
Multitenant -- the container database architecture.. the first database designed for the Cloud.
Oracle has introduced Oracle Multitenant architecture with the release of Oracle Database 12c R1 on July 2013. It has been eight year now by the time I am writing this Article. You can find many Articles on Multitenant and I am adding one more in the list of the same.
I found few reasons to write this article as below,
1) Still many DBAs are not using Multitenant or haven’t got chance to work on it.
2) Many organizations are still on 11g or 12c with single instance database.
3) 20c Onwards, it is mandatory to have container database architecture at the time of installation itself.
4) Enabling DBAs to learn Multitenant architecture.
5) Helping DBAs to simplify their day to day activity and reducing administrative work.
1) Still many DBAs are not using Multitenant or haven’t got chance to work on it.
2) Many organizations are still on 11g or 12c with single instance database.
3) 20c Onwards, it is mandatory to have container database architecture at the time of installation itself.
4) Enabling DBAs to learn Multitenant architecture.
5) Helping DBAs to simplify their day to day activity and reducing administrative work.
Here, I am writing series of articles on Multitenant, you can also go through the same and see how easy to administrate CDB/PDBs.
And finally, I would like to share,
Now, let's understand Multitenant architecture and it's core concepts,
Multitenant Architecture
Before Oracle Database 12c, each database is having their own instance and each database requires its own processor, memory and other server resources. Most of the efforts were going to manage those individual instances, in terms of patching, migration, upgrades and performance tuning.
In addition to management issues, these databases often waste server resources because they use only a very small portion of dedicated server. Hence consolidation of these databases into a single database Oracle introduces Multitenant option, which run one or more Pluggable Databases (PDBs) within a single Oracle instance, called a multitenant Container Database (CDB).
Following image shows multitenant architecture.
Just to give brief understanding, This is multitenant architecture;
you can found this poster in Oracle Documents.
As you see, we have single instance which consist of
common memory area and background process for all PDBs and common set of sys,
sysaux tablespace, redo log files, archive log file.
But we have different set of files at PDB level. PDB have their own sys and sysaux tablespace to store PDB level meta data and user tablespaces, local undo and temp files.
In PDB, one users cannot access to other PDBs data, only common user have some credentials to manage PDBs all at the CDB level. Here you can have different set of duties assign at PDB level and CDB level.
Following is the detailed architecture of Multitenant.
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Key Benefits of Multitenant
If you are adopting multitenant architecture, your application will run without change. Also you will get benefits of rapid cloning. You can plug and unplug non-cdb database into container database as PDB.
As Operation perspective, you can manage many database as one. Less operation on DB like patching an upgrade.
Using this approach, you will get benefits of consolidation of your hardware + software i.e database.
Using Multitenant, you are consolidating all your database, my mean to say that database resides on multiple server will now be on one server as pluggable database. This directly benefits you in your capital expenditure.
Also operation wise you are managing many db as one so it will helps you to do upgrade or patching as one activity for all rather doing multiple times. Provisioning of new PDB is also simple
Dev and testing team will get database ready in couple of minutes via cloning or snapshot cloning. Database can be plug and unplug from one CDB to another CDB easily with few steps.
This is really very easy to adopt multitenant in your environment. Just need to understand the core architecture for the same.
Key Benefits for DBAs
There are several features introduce in multitenant gradually from 12c to 19c. Plug & unplug of PDBs, PDB cloning, Hot clones, flashback PDBs, PDB level AW reports, initially in 12c R1 AWR report was only at CDB level. But after that it is possible to take AWR report at PDB level.
You can manage cpu/io/memory at PDB level with resource manager. You can have Refreshable PDB, Dataguard at PDB level. And also you can have keystore for each PDBs. PDB lockdown profiles , that helps you to restrict user to run commands such as alter system, alter session, accessing of common objects, AWR reports etc it is very useful from security perspective and separation of duties among users.
Multitenant Features specific to DBAs
PDB Level Operations
Plug and Unplug
PDB Hot Clone
Refreshable PDB
Snapshot Carousel
Online PDB Relocation
High Availability with PDBs
Flashback PDB
Dataguard at PDB level
PDBs Level Monitoring and Diagnoses
PDB Level AWR Report
PDB Level Resource Management
Keysotres for PDBs
CDB Fleet Management
Security
PDB Lockdown Profile
Oracle Applications Certified with Multitenant
Here are list of Applications that are certified with Multitenant. Other custom application build different programming languages are also supported for Multitenant. Also Multitenant support Microservice architecture.
Fusion Applications
Fusion ERP
Fusion HCM
Fusion CRM
NetSuite
Applications Unlimited
Siebel
PeopleSoft
JD Edwards
Oracle Cloud Applications
Taleo Business Edition
RightNow
Oracle Argus Analytics
Oracle Utilities Mobile Workforce Management
Oracle FLEXCUBE Direct
Oracle Argus Mart
Supply Chain
Oracle Utilities Customer Care and Billing
Oracle Argus Insight
Oracle Utilities Work and Asset Management
Retail Analytics
Oracle Argus Safety
Planning Non-RPAS
Oracle Utilities Smart Grid Gateway
Merch Suite
Oracle Utilities Meter Data Management System
Stores Suite
And Many More...
Multitenant Announcement so far…
- Multitenant came up with 12c release. Oracle is more focusing on Cloud and Multitenant deployments and hence oracle has deprecated non-cdb architecture with its 12.1.0.2
- And 19c onwards, Oracle provides you 3 PDBs without multitenant license. This will encourage all of us to use CDB/PDB architecture here.
- And now 20c onwards, non-cdb architecture will be de-supported. So here it is mandatory for all of us to learn more about multitenant and its features and how to use it.
References
Thanks & Regards,
Chandan Tanwani
Oracle Performance Tuning Certified Expert
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