Trang,
Theoretically, the online redo log files are
be necessary, but the world has a habit of making a shambles of the
theoretical. Let's say, in the event that you automate your Friday
script, you'll probably come to realize that SHUTDOWN IMMEDIATE is far from
perfect (as well as far from immediate!). Over time, you'll probably
construct some kind of "fail-safe" mechanism to SHUTDOWN ABORT if the initial
SHUTDOWN IMMEDIATE doesn't shut down after a period of time. Pretty
standard thing that DBAs have been writing for years. Hopefully, after the
SHUTDOWN ABORT they also STARTUP RESTRICT and then SHUTDOWN NORMAL, but you
can't count on it...
So, here's the point: what if you take a cold
backup in NOARCHIVELOG mode after a SHUTDOWN ABORT (that should have been a
SHUTDOWN IMMEDIATE and wasn't) and you have *not* backed up those online redo
log files? Answer: unusable backup. So, back up everything:
all datafiles, controlfiles, and online redo logfiles. The latter are not
too big anyway -- what's the point of excluding them?
It is wise to take a cold backup after a clean
shutdown, but you can even get a valid backup after a SHUTDOWN ABORT or a crash
if you've backed up the online redo archive log files. When you restart
Oracle, an instance recovery will occur automatically, and you might not
even know it. Just be certain that the instance is truly "dead" when
you take your "cold" backup...
With regards to switching between ARCHIVELOG and
NOARCHIVELOG, it's a waste of effort from a recoverability standpoint. At
most it may be interesting, but as soon as you switch out of ARCHIVELOG mode,
nothing you've done while in ARCHIVELOG mode is valid anymore. Leave it
one way or the other, and then leave it...
...just my $0.02...
Another $0.02: use RMAN for your cold
backups. Then you won't forget anything, because RMAN will remember for
you...
Hope this helps...
-Tim
|
- Re: Database backup question. Tim Gorman
- Re: Database backup question. Connor McDonald
- RE: Database backup question. Steve McClure
- Re: Database backup question. Jared Still
- RE: Database backup question. Sherman, Paul R.
- RE: Database backup question. Whittle Jerome Contr NCI
- RE: Database backup question. Gogala, Mladen
- RE: Database backup question. Jesse, Rich
- RE: Database backup question. Sherman, Paul R.
- Re: Database backup question. Joe Testa
- RE: Database backup question. Gene Sais