SAP HANA System Replication - DR test
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?
Steve SOUMAH replied
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.