You can use expdp and impdp utility by Oracle for migration of database from 11g to 12c.
First of all we will use expdp utility to export the whole database into a dumpfile (.dmp) by issuing the following command:
expdp system/password@db11g full=Y directory=TEST_DIR dumpfile=DB11G.dmp logfile=expdpDB11G.log
Here, FULL parameter indicates that the whole database will be exported
Directory --> The directory on server in which you want to place the dumpfile
DUMPFILE --> The name of dumpfile
LOGFILE --> The name of logfile (that logs the status of export process)
After the export is done successfully you will get something like:
Job "SYSTEM"."SYS_EXPORT_FULL_01" successfully completed at 10:35
Now, your whole database is stored in a dumfile(.dmp) in the 'DIRECTORY' mentioned in the expdp command.
We will now start import of the database into 12c database with the help of impdp utility.
impdp system/password@db10g full=Y directory=TEST_DIR dumpfile=DB11G.dmp logfile=impdpDB12c.log
*Before starting import you might need to transfer the dumpfile to the new server (i.e. 12c)
After import has been successfully completed you will get successfull completion message.
Reference link --> https://oracle-base.com/articles/10g/oracle-data-pump-10g
Happy Migration !!
You can run upgrade advisor 2014 on a backup of your current to-be-migrated database which in your case is sql server 2008R2.
I have written detailed steps on migration here.
PowerShell based start-sqlmigration is what I highly recommend (I am using it quiet often to migrate server instances to new server) when you have to migrate your entire server instance.
e.g.
Start-SqlMigration -Source sql2008R2 -Destination sql2014 -BackupRestore -NetworkShare \nas\sql\migration
Make sure that the sql server service account has proper permissions on the NetworkShare
Best Answer
I've had to do this and just had a record available for the old server. Renamed the DNS entries and did a ipconfig /flushdns on the servers themselves since they were replicating back in case of a failback. We set the DNS to a very low TTL so clients also got updated. Powershell made all this very easy and fast.
If your clients are easily identified and you have access, you can do a flushdns yourself on them as well. I recorded and documented all connections going to the database prior to the upgrade so I knew all the clients to look out for. Then finally I set the old database to block all users except the sole one I was using for replication on the old machine and ran traces to see if anyone was attempting to connect to the old instance. None did but if they were, I would inform them to update DNS or check their connection string.