Re: Worst Admin Mistake? was --> Re: /usr broken, will the machine reboot ?

[Andrew McGlashan <andrew.mcglashan@affinityvision.com.au>]

Hi,

Walter Hurry wrote:
> On Thu, 15 Sep 2011 20:34:38 -0300, D G Teed wrote:
>
> > I was hunting for the disk hog using the curses based ncdu utility. I
> > found a large tar file which could be deleted without issue. It was in
> > an oracle production directory area.  Due to a bug in ncdu, (
> > http://sourceforge.net/tracker/?
> func=detail&aid=2829950&group_id=200175&atid=972449)
> > it didn't delete the highlighted item, but the one next to it, which was
> > the oracle production database.  Recovery was easy to do from snapshot
> > files from the database.
>
> I don't think that is the full story. Oracle databases do not consist of 
> a single file; there are many. Control files, tablespace files, undo 
> segments, redo logs, etc, etc. And if the database is properly organised, 
> loss of a single file should not present any problem at all.

A datafile might be deleted, a running database _might_ still keep it in
use [depends on the OS and file system type], but when the database
instance is shutdown, then the file could easily go.  A datafile could
be very large, control files and redo log files are small (generally).
Archive logging needs to be in place and the archived log files need to
be available together with a hot backup of the effected database file
for recovery.

--
Kind Regards
AndrewM

Andrew McGlashan
Broadband Solutions now including VoIP