April 9, 2017
Recently I spent pretty good amount of time trying out RMAN & was able to apply what I learned at multiple production environments those were purely depending upon export dumps over a decade. Once after committing many hours for recovery using RMAN to a standby instance, I started wondering whether such efforts are really worth for a database that was hardly couple of GBs after 10+ years of data collection. I read many articles from reputed Oracle related sites, including this one.
A majority of the small scale industries don’t invest on DBAs because, FOR them DBAs are found doing “nothing” at all throughout the salary periods & most of them have unmatched ego that don’t allow them to learn anything other than what they are “certified to”. I have some pretty bad experiences with bunch of DBAs who didn’t even have a clue about SGA, PGA setups for a 10g database because they were “Certified” for 11g
Throughout the years, we have many hardware crashes and always restored the database(s) from export dumps (.dmp). A clearly documented schema/tablespace details were all we needed as the data that was expected to be restored were always sized in few GBs.
An Oracle developer with moderate database skills could, within an hour time can go online with the database restored using the simple import, which may not be the case with RMAN. RMAN strongly depends upon many factors for backup, restore & and from my limited DBA skills, should be adapted to bigger database environments.
So, you have a very small database and want to restore it from a dump file after a hardware crash or while switching to better hardware, you are very happy to know that importing from a dump export is much easier than RMAN (as you don’t have a clue what it is). Is it a fail proof method? Well, depends. If you are dealing with a hardly documented environment, you can land in hot soup with import screaming about non-existing objects referred by the currently imported schema. An interesting discussion you may find here that is closed as answered once after I confirmed it.
Obviously, I started the topic explaining how easy it looks to use pure dump files for restoration purposes, however ending the topic by saying that if you have a supported database, please implement RMAN immediately, which is a beautiful piece of technology helping you to recover the entire database with moderate level of DBA skills.