Oracle Dataguard Why you need HSBC TECHNOLOGY AND

Oracle Dataguard – Why you need!

} HSBC TECHNOLOGY AND SERVICES Agenda } } What is the purpose of Dataguard What is the difference between RAC & Dataguard What is the difference between a Dataguard & Replication Solution What is main thing that make databases synchronized in dg, gg, streams or any other replication? © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES What is Dataguard? } Oracle Dataguard synchronizing the database changes to ther other databases. } Used for disaster recoveries. } Typically located in other datacentres } Used Heterogeneous method i. e oracle-oracle © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 2. WHat is difference between rac and dataguard } RAC is used for high availability, DG is to provide disaster solution } Typically RAC nodes located in same data centre if a natural disaster occurs and the data center has issues or any hardware failures, until it resolved business can be resumed } Hence , we need a solution to keep the databases available to tolerate the disasters or hardware failures we will need to have Dataguard solution in place in different data centre © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 3. Difference between DG/Streams/Goldengate } Golden. Gate also synchronizes the databases (replication) , solution for replication a subset of data or complete database } Golden. Gate is also provides heterogeneous replication, db 2 oracle, oracl 2 -db 2 } Dataguard works only for oracle-oracle synchronization. } Further, streams also uses same replication method like GG but as such the replication process runs inside the database so its merely oracle-oracle synchronization again © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 4 What is required to have replication/Dataguard } Redo Log/Archive Logs Shipping to target – Typically all the database changes logged into } Redo Log Buffer } Redo Log file } Archive Log File } This logs will be used to re apply those statements in the target environments for DG/GG/Streams © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 5 Okay-We want Dataguard then, but } We want to know the database is operated? } Ans: It Depends, Since you have two options Physical Standby Logical Standby Mount Mode - Readonly Read Write Allowed to Query/Write Cannot create your own objects Can be kept on readonly with active dataguard Offload backups / Reporting Offload backups/reporting © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 6 Hold a sec, when we want can we test some releases in Dataguard Environment } Scenario: We have a big release which is critical but we do not have production database like test environment to test, shall we use the dataguard environment to do testing and you can revert back to original state. } Answer: Yes, by using Snapshot Standby is introduced in 10 g, and it uses flashback logs to revert back the changes, High Level Steps: 1. Stop the MRP process 2. Alter database convert to snapshot standby; 3. Shutdown immediate 4. Startup mount 5. Alter database open; Note: - when you convert the physical to snapshot it internally creates a restore point and when you revert back you can take database to previous state all changes vanished. © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES 7. Well, so far so good, one question } How about Disaster testing? } Answer: Well you can transition the roles Typically Dataguard allows to transit the role from primary to standby and vice versa. When you want to do Disaster Testing, you can switch over the standby as primary and primary as standby. When in real situation of failures, you can really activate the standby as primary. © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES Okay, good, How do we get there. . } What you need to create a Data guard environment? } } } } Need same server/hardware like Production Need to have same level of Operating system Need to have same version of Oracle Installed (if physical standby) Can have different version of oracle Installed (if logical standby) Network Bandwidth to support redo shipping Storage capacity as like Production If RAC, create same nodes as like production. – Note: The storage filesystems can be different like } ASM to NON –ASM } NON-ASM to ASM } /u 04/oradata to /oradata/STDBY © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES Hold a sec, can we have DG in windows } Question: - Can we create standby in Windows and our primary is in Linux } Ans: - Yes, not only that you can have 32 -bit and 64 -bit as vice versa } Ans: - You can also have 11 g to 10 g in logical standby © HSBC Holdings plc, 2009. All Rights Reserved.

} HSBC TECHNOLOGY AND SERVICES Nice, lets wait for a week we will provide you server } And clock ticking… } Meanwhile lets look at the Architecture. , Bits and pieces. © HSBC Holdings plc, 2009. All Rights Reserved.