I am working on database upgrade and migration project for one organization. We have about 200 databases in Prod, Dev, Test and Implementation environments.
The current source database settings are: Oracle 11gr2 single instance on Solaris 10 with file system.
The future target database settings are: Oracle 12r2 single tenant on Solaris 11 with ASM file system. The servers are different physical servers.
Now I am thinking about the best and the fastest methods to migrate these database from 11g to 12c. of course, we will test in DEV environment first and get all information, issue and step by step procedures. Then apply it to other environments.
So the question is: what is the best method to accomplish this job. Based on Oracle documentation and other gurus' online posts. I have picked up some methods with my concerns and questions. I would like to hear from all experts in this forum to
provide me the feedback and to help me to choose the best method for this project. Many thanks to your help in advance.
The major methods I think is workable for our situation:
1. Migrate 11g DB to 12c ASM using RMAN. There are many preparing process. The major RMAN command is
$backup as copy incremental level 0 database format '+DATA' TAG 'ORA_ASM_MIGRATION';
$switch database to copy
This one is easy to convert file system to ASM and RMAN is very reliable.
2. Migrate 11g DB to 12c ASM using RMAN duplicate
$rman target / auxiliary sys/xxx@dupdbaux
run {
allocate channel c1 type disk;
allocate auxiliary channel c2 type disk;
duplicate target database to dupdb;
}
This method need very good network configuration and two separate servers and databases may be not efficient.
3. Migrate 11g DB to 12c ASM with Full transportable tablespace expdp/impdp. I do not list the detailed steps here. My concerns are: We need to convert all data files in 11g file system to 12c ASM system. We can use RMAN ro ASMCMD to convert the files. But for huge database with hundreds of data files. Conversion is a big job.
4. Migrate 11g DB to 12c ASM using expdp/impdp data pump. I also do not list the detailed steps here. My concerns are: How to convert the 11g filesystem files to 12c ASM files in thos method? One way is: create new tablespace in 12c ASM diskgroup. Only expdp/impdp user data into new tablespace by using remap in impdp. (metadata has been created when create CDB/PDB) In this way, no file-system conversion is needed. But the tablespace on 12c will be different from tablespace on 11g. (Application does not care about this. Right?) The data will be the same. For huge database with many tablespaces created in 11g. we have to create many tablespaces in 12c ASM and remap them during IMPDP. That also cause a lot of works. If I create one bigfile tablespace in 12c ASM to remap with many tablespace in 11g filesystem. Is this a good practice to do it?
There also are some other methods for database migration and upgrade. But I only prefer above these methods. Please feel free to feedback me your opinions and suggestions. Thanks again.