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

Well this is just guesswork,
 but I'd bet that you cannot bounce the database once the files are gone.

 What you see is probably more of a unix feature than anything else.  When you rm something, the actual disk space is not released until all running processes close the filehandle on the 'deleted' file.

 Since your instance was running, it could simply use the filehandle that was opened _before_ the file got removed.

 you should also observe that the disk space usage (df -k ....) does not change until you terminate the instance....

Karsten

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
Received on Thu Jul 17 2003 - 10:24:00 CDT