SAP HANA System Replication - DR test

[Former Member]

Hi

We need to perform a DR test of our HANA replication system.

From administration guide I can see the steps to:

• Perform a takeover - making a secondary system functioning as primary system.
• Failback: back to original setup

But for DR test procedure, we need to make secondary system available for test queries, and after DR we need to Failback to the Original Primary System, which should not have been changed by the DR testing. 

What would be a best way to accomplish this? 

Is it possible in HANA to

•      create a DB savepoint in HANA before stopping Primary system and fall back to it?
•      Open secondary system in read only mode?
•      Other suggestions please?

Thanks

Willem

[former_member182307 · Accepted solution]

Hello,

I wrote some documents about DR tests.

You can find them here :

Hope this helps,

Best regards,

Steve.

[Former Member · Accepted solution]

Hi

Thanks for the links, they were impressive.

My test case is a bit different, I want to:

* Stop Primary

* Take over Secondary

          -- Run tests on Secondary

          -- Stop Secondary

* now, we may not let the changes of the DR test affect the original Primary Database, so we will not be performing a Replication failback.

To get environment to initial state before DR testing started, will it be possible to change Secondary node back to a "syncmem" mode after DR testing..?

Kind Regards

Willem

[former_member182307 · Accepted solution]

Hello Willem,

In fact, when you switch the secondary to primary, this does not mean that you affect the primary node.

I could see this in my test case.

I'm used to Oracle dataguard switchover procedures for example, and with this configuration you revert the roles.

For failover with Hana, it works just like a failover with Oracle by the way, the secondary becomes primary, without changing the role of the "initial" primary.

This means that at some point you have 2 primary databases running.

The first on the primary site. The second on your DR site.

Then what you could do would be , activating the DR as primary, letting the "initial" primary running. You do not perform any DNS switch. Then you can access your DR DB through its DR hostname.

After that, you'll have to rebuild the DR as you did the first time.

In our tests, we are used to perform some real DR tests, ie, really switching the systems to DR sites, letting users work on DR and then perform the "switchback" to the primary site without losing data.

HTH,

Steve.

[Former Member]

Hi Willem,

Please follow the recommended best practices as per the below SAP note for accomplishing a takeover and failback using HANA System replication

The highlighted section from the SAP note clearly identifies the steps involved and easy to implement

http://service.sap.com/sap/support/notes/1945676

Let me know if you have any questions

Hope it helps

Sunil