Re: Removing all datafiles doesn't bring down the database

jeffyee_at_hotmail.com (Jeffrey Yee) wrote in message news:<ec4cec95.0307170154.5727fd96_at_posting.google.com>...
> Hi,
>
> I'm running Oracle9i 9.0.1 on HP-UX 11i. I simulate a disk crash by
> removing all the datafiles. To my surprise, the database keeps
> running, and I can still do queries, update, commit, and alter system
> switch logfile.
>
> But I'm confuse how this can happen. A switch logfile will cause a
> checkpoint, causing dirty buffers to be written to datafiles, which
> are missing.
>
> Even better still, after I restore & recover, I can see those commit
> that was done after deleting all the datafiles.
>
> Is this something new in Oracle9i? Is there anywhere I can get more
> information on this matter. I'm interested to know the architecture
> behind this. I would assume most of the stuff is stored in the redo
> logs.
>
> Please advice. Thank you.
>
>
> Best Regards,
> Jeffrey Yee

Jeff, What kind of file system are you using: ufx, raw, third party, etc...?
In UNIX if you use rm (remove) on a opened file the file does not actually go away until the using program closes it. That might explain part of what you saw, but it has been a long time since I played with removing files from under Oracle. The board would need more details on the file system and exactly the order of your operations to explain what you saw.

HTH -- Mark D Powell -- Received on Thu Jul 17 2003 - 07:46:41 CDT