Re: rename datafile without shutting down

In article <86shfi$d2p$1_at_nnrp1.deja.com>,   Christ Follower <christ_follower_at_my-deja.com> wrote:
>
> I can't do that because the application has to "write" to the
database.
> I was trying to "fool" Oracle to write to redo logs and spare the data
> file while I was doing my business. I noticed that a few posters
> mentioned that Oracle still writes to datafile even in backup mode. I
> can't be sure if this is true. If a process is writing to a file, the
> file remains open. Then, any O.S. copy may fail because O.S. also has
> memory buffer handling file I/O! I believe Oracle process stops
writing
> to datafile if a tablespace is in backup mode. Unfortunately, there's
> no way to rename a datafile while it is still online. This fact
> answered my original question: Q: Is is possible to rename a file
> without down time? A: No. Sad. It seems Oracle has almost everything
> needed there but logically the engine does not allow that.
>

Yes it is true that Oracle writes to the tablespace files while the tablespace is in backup mode. That is why it is called a fuzzy image and archived redo logs must be applied to create a consistent image. You can prove this for yourself by watching the IO statistics in v$filestat change for Oracle activity while your OS copies are running. Oracle does not have any way to track the OS activity so it is reporting only its activity.

You can check out the Backup and recovery manual for more details. --
Mark D. Powell -- The only advice that counts is the advice that  you follow so follow your own advice --

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Before you buy. Received on Fri Jan 28 2000 - 12:25:46 CST