Re: Question in HOT BACKUP
- From: Jeremiah Wilton <jwilton@xxxxxxxxxxxxx>
- To: Chirag DBA <ChiragDBA@xxxxxxxxx>
- Date: Sat, 2 Oct 2004 03:28:13 -0700 (PDT)
On Sat, 2 Oct 2004, Chirag DBA wrote:
> When I was asked which filese I will copy for hot backup, I said redo too.
>
> Cause I think they can help us always to recover database upto point of time.
>
> I was pulled a lot, but my only question that if not redo then how
> will you recover yr DB upto point of failure, stopped the arguements.
Askdba removed from the distribution.
If you can win the argument, you must be right! Anyway good for you
for checking on this even though you convinced the interviewers you
were right.
The reason that many people recommend against backing up online logs
during hot/cold backup is twofold:
1. If you back up the current online log, you have no guarantee of
obtaining a clean copy since log writer might be halfway through
performing a write. You should obtain the most recent log by
archiving it (archive log current).
2. If you restore a backup including the online logs (in their normal
location) and the controlfile is also restored in the normal location,
then the restored database can be brought up in such a way that crash
recovery would take place automatically without prompts, and there
could be no opportunity to apply archive logs to roll the database
forward to a future point in time.
It is likely that you might want to recover past the point in time of
the backup, thus the online logs would be nowhere near the most
current logs for the purposes of a restore/recover exercise.
--
Jeremiah Wilton
http://www.speakeasy.net/~jwilton
--
//www.freelists.org/webpage/oracle-l
Other related posts:
