SharePlex vs RMAN

Question

Hello All, 
 I have been working on Oracle Golden Gate quote long time but I was asked to do some POC in Shareplex for upcoming migration. 
 From yesterday I'm reading Shareplex 9 with lots of documents but found lots interesting. Specifically, The below links has lots of details. 
 https://gcn.com/~/media/GIG/GCN/Whitepapers/Quest_Top%205%20Reasons%20to%20Choose%20SharePlex.ashx 
 Unfortunately, I'm not able to find what I'm looking. 
 1. Is RMAN fully integrated with Shareplex ? Let say, I have multiple terabyte database which I'm looking for application migration / and database migration from one version to another version. In this case, I would like have to start RMAN backup and start with SCN like Golden Gate . 
 Is it possible in shareplex ? Or only option RMAN Image backup ? If RMAN image backup then it may require downtime in source database. Is that correct ? 
 2. In Golden Gate, We have option to do one time data copy. I mean initial data sync using DATA PUMP.. I can use this feature for smaller database. Is it possible from Shareplex ? 
 Thank you. Babu

Tom.Chu · Answer

Hi Babu, 
 
SharePlex has 2 methods when starting replication. Like GoldenGate, you can start SharePlex replication from a starting SCN and use your known method for synchronization. With this method, I always feel there is a mishap waiting to be happened. With a busy database, from an SCN which is a specific location of the redo/archive_log, all open transactions has to be taken care of. If you have many long running transaction, the product has to go back in time to get the full transaction. With that said, there is a second method that SharePlex uses to start replication. 
 
1. Start replication - hold data in the queue file till you ready. Let say this is at 1:00PM. 
2. Instantiate your target from RMAN backup. You can recover until cancel and keep shipping log to the target and make sure the recovery is past the time of starting replication (1:00:01+). With this, you ensure that all open transactions are taken care off so no mishap. 
3. run the reconcile command on the target to remove all duplicate transaction. SharePlex can use SCN or last full log apply. 
 
This method has been proven since 1998 so it well full proof. 
 
About Datapump, you can use the same method above and use reconcile to SCN and you should be fine. There is a bit different in the SCN that you use for reconcile in this method. You will need to use SCN+1 since datapump will include the SCN for recovery while recover until in the RMAN will not. 
 
If you have more questions, please feel free to give us a call and we can explain in more detail. 
 
Thanks... 
Tom