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

Feature of the Unix filesystem. Has nothing to do with Oracle. The files are still there, because they are in cache. However they are ready to be overwritten, and if you bounce the system, your database will be toast.

Sybrand Bakker
Senior Oracle DBA Received on Thu Jul 17 2003 - 08:36:17 CDT