Compressing Oracle backups and data files

Oracle Database Tips by Donald Burleson

Oracle backups are very critical to any business and the Oracle DBA strives to implement a fully-tested, fully supported backup and recovery procedure.  I recently received this interesting question:

QUESTION: 

I have been told by an Oracle support representative that tarring and then gzipping a datafile is not supported. That is, during the uncompressing phase, the datafile may be corrupted or unusable. What do you have to say about this topic?

Have you ever successfully recovered a database using the uncompressed version of the gzipped file?  Oracle stated that when you uncompress the gzipped datafile, it will be unreadable and therefore you will not be able to recover the database with it. I plan to definitely test this out, however, I would love to know if you have ever experienced any problems with the recovery phase.


ANSWER:

If you really need to do this, and it's not supported by Oracle, the best way to see if it is working is to run some samples. You can use the "diff" command and "checksum" to see if the compressed-uncompressed files remain the same. The more tests you make, the higher your confidence in the procedure and you can access the risks yourself.