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I have 30.7GB backup file generated from RMAN. The original ./datafile is 950.28GB. According to previous DBA, there is a lot of free space in table space. Now, I have 300GB free disk space in hard disk. How can i restore the backup file using limited disk space ? Thkb4

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One of the first things Oracle does at restore time is pre-create the data files to the defined size. So you do need a way to store the full size of the files. A compressed filesystem could be used for that and with a little luck it works. It just does not solve the problem.

What you do want is to re organize the source database. The quickest way is to prepare a new database with correct sized tablespaces and datafiles. Next use datapump to transport the schemas to the new database. If needed, this can even be done online by using smart tools like dbvisit replicate (or goldengate if money is of no importance). Trash the old database when the two are in sync.

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One of the possible solutions could be to employ file system with online compression. Examples:

  • BTRFS if you have recent Linux distribution
  • some FUSE filesystem with compression. E.g. fuse-zip

Fuse-zip is available from RPMforge so one does not have to compile himself.

Of course I would not use this for production database but just for restore - why not?

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