Why is multi tenant conversion irrevocable?

[former_member210392]

Hello experts,

I have been trying to understand the HANA Multi Tenancy architecture. One of the first statements I can across is when a conversion is done from a single tenant to multi tenant, this step is irrevocable. Why is it irrevocable?

Is it correct to think of a multi tenant HANA DB as a database within a database or would that be incorrect? How does multi tenancy in HANA differ from having multiple databases within one MS SQL installation?

Cheers!

Dan

[Former Member · Accepted solution]

The primary difference between a Single container and the Multitenant Database container(MDC) is the SYSTEMDB. During the conversion from Single container to MDC a SYSTEMDB is created

This SYSTEMDB now has the following services nameserver, preprocessor, compileserver, daemon, webdispatcher for the entire HANA system(no INDEXSERVER service)

For each new Tenant Database created an INDEXSERVER service and the volumes are created

Due to the Architecture of SYSTEMDB and Tenant Database currently the conversion from MDC to Single container HANA system is not available but as per SAP Note 2104291 it is being considered by SAP for future versions

The picture from the below link helps to understand the difference in Architecture of different HAN systems in comparison to MDC

http://1h9mo84f79012h5z12640ehs-wpengine.netdna-ssl.com/wp-content/uploads/2015/01/mdc-1.jpg

The SAP note 2096000 is very useful to understand MDC configuration

Hope this helps

https://websmp130.sap-ag.de/sap(bD1lbiZjPTAwMQ==)/bc/bsp/sno/ui_entry/entry.htm?param=69765F6D6F6465...