SAP HANA High Availability

[subhadipkumar]

Hello Experts,

I'm looking for suggestion here regarding HA setup for SAP HANA. We are trying to build one of the small system on HA as Proof of Concept.

However I'm not getting general documentation what setup I need to make when the HANA DB failover and switch to Standby Host.

How SAP application server will determine that DB has switched to standby host?

What kind of setup I need to do at software level?

Do I need to do any kind of setup at Network level?

If you can refer me to any document or any other SCN note that explains this that will be really helpful.

- Subhadip

[Former Member]

Hi Subhadip.

There are several HA types:

For the Standby / Failover please take  a look at this document:

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/40970693-a3a4-3210-fb99-bb5757d23...

Regards.

Osvaldo Dias Ferreira

[subhadipkumar]

Hello Osvaldo,

I've no doubt HANA DB failover or HANA DB HA Setup - I understand how it failsover to standby node.

However I'm looking for suggestion how SAP Application server will switch to standby DB host in case of failure.

- Subhadip

[Former Member]

Hi.

I dont clear understand your doubt.

But send you one more document that are important and can help.

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/9049e009-b717-3110-ccbd-e14c277d8...

Regards.

Osvaldo Dias Ferreira

[subhadipkumar]

Hi,

Thanks. I mostly looking for Client Connection Recovery section and need more details on the setup size to make it automated. We are running on SPS08.

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6.2 Client connection recovery To perform the takeover only on the SAP HANA system will, in most cases, not be enough. Somehow the client or application server needs to be able to continuously reach the SAP HANA system, no matter which site is currently the primary. There are several methods: • IP redirection: A virtual IP address is assigned to the virtual host name. In case of a takeover, the virtual IP will unbind from the network adapter of the primary system and bind to the adapter on the secondary system. • DNS redirection: In this scenario the IP for the host name in the DNS will be changed from the address of the primary to the address of the secondary system. Both methods have their advantages but it will be mostly decided by the IT policies and existing configuration. If there are no existing constraints, IP redirection has the clear benefit of being faster to process in a script rather than synchronizing changes of DNS entries over a global network. 20 How To System Replication for SAP HANA Since SPS09 SAP HANA offers the so-called HA/DR providers which are capable of informing external entities about activities inside SAP HANA scale-out (such as Host Auto-Failover) and SAP HANA system replication setups. In a Python script actions can be defined which should be executed before or after certain HANA activities (like startup, shutdown, failover, takeover, connectionChanged, ...). One example for these so-called hooks is moving virtual IP addresses after takeover in SAP HANA system replication. Additionally external cluster management software can be used to perform the client reconnect after takeover.

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