I'm building a Dataguard test environment to validate if it is possible to have a configuration where:
Option 1 seems to be validated by SAP (1431241 - RAC with TAF) for RAC, thus should be ok with Dataguard.
This has already be documented by Kjell Erik Furnes in this great POC: HA SAP on Oracle DataGuard
I'm just a bit concerned about the problem with the FAILOVER_MODE option set to PRECONNECT that is according to Kjell making failover quicker but is not compatible with R3trans (should use BASIC mode as stated in note 562403 - FAQ: Oracle Net)
For option 2 I did not find any 'official' information from SAP.
Note 105047 - Support for Oracle functions in the SAP environment tells that the Data Guard Broker is supported but I did not find any information about FSFO except Oracle documentation Oracle White Paper—Setting up Oracle 11g Data Guard for SAP customers (page 8).
So is FSFO fully supported/validated by SAP?
Does anybody ever use FSFO + TAF?
Thanks for you feedback,
Thanks for the information.
I did already open an OSS message on that topic, but sometimes you get quicker and wiser answers from SDN
I'm currently reading all the documentation on FSFO, not as easy as reading a single SAP document... it's a tough time ;-)
Can you please confirm that to install the observer you need to install the client administrator wth OUI ?
Where did you install the observer?
I think I'll install it on one of the SAP AS.
I did get an answer from SAP...
FSFO have not been tested by SAP, though we do not see any technical reason for that not to be used.
So you can use this feature, but you will not have technical support from SAP if you come up into an issue related to this feature. All otherfeatures will still be supported by us in case you decide to use FSFO.
I've asked also how to get some support from Oracle as far as SAP users does note have access to Metalink any more (since more than a yeaur now... a real shame !)
In case you need support for FSFO you can open a message and we'll involve Oracle to help you with the issue.
i think you are mixing up two things here (TAF and FAN). There are two nice white papers, which describes each in a DG environment and how they interact together.
However - yes it works fine in a SAP environment.
Thanks for the information.
TAF & FAN are just two sides of FCF... Oracle has too many acronyms for that mechanism.
It's all about activating FCF (Fast Connection Failover) through FAN (Fast Application Notification) & TAF (Transparent Application Failover)... obvious !
Wish I had some clear statements from SAP on that point...
If we have setup an DG broker + observer it is just a matter of configuring , FAILOVER , FAILOVER_MODE and CONNECT_TIMEOUT parameters in the TNSAME files of SAP AS.
You can use Oracle Notification Services (ONS) to immediately notify clients of the failover of services between the primary and standby databases. The Oracle Data Guard Broker uses Fast Application Notification (FAN) to send notifications to clients when a failover occurs.
My concerns are more on the FAILOVER_MODE method option, if set to BASIC as recommended by SAP the client reconnection might fail. If set to PRECONNECT R3trans might fail.
Well the proof is in the eating... so I'll test this by my own, and keep the thread updated.
sorry is still don't get your point why you concern about the FAILOVER_MODE and PRECONNECT in a DG environment, because of your service is not available on standby site before a FAILOVER or SWITCHOVER. So the connect to the backup instance will not work.
Have you check the described procedure in the white paper?
OCI Clients: Notification and reconnection is accomplished for OCI clients in a Data Guard configuration using Fast Application Notification (FAN) and Transparent Application Failover (TAF) in the following manner:
• When an OCI client makes a connection to a primary database, the REG$ table is updated to includes the IP address for the client. This data is automatically replicated to the physical standby.
• Upon failover, the Data Guard broker inserts a DB Down event into the database alert queue on the standby which is then sent to all clients having an entry in the REG$ table. Note that this method of automating client failover requires the failover to be managed using the Data Guard broker.
• When clients receive the DB Down event they immediately disconnect from the failed primary.
• TAF enables OCI clients to automatically attempt to create a new connection to the service 'sales', used in the above example.
So your OCI client gets the information about the FAILOVER / SWITCHOVER and tries to reconnect immediately to your defined host(s) with the available service. DG is not RAC and you have the (connect) service only available at your primary site.