RE: Backup Controlfile and ArchiveLog -- was re Urgent ORA-00600: internal error code
- From: Hemant K Chitale <hkchital@xxxxxxxxxxxxxx>
- To: "Mark W. Farnham" <mwf@xxxxxxxx>
- Date: Sat, 05 May 2007 00:47:30 +0800
Yes, besides the fact that the Data Dictionary check can make files
go "MISSING",
the OPEN RESETLOGS actually *initializes* your online redo logs.
So, it does make sense to backup your online redo logs that are ondisk,
with the datafiles before the OPEN.
If your OPEN crashes -- and I have seen that happen a couple of times
(eg missing or incorrect UNDO), block error etc --- then you can still
re-attempt with the backup of the datafiles and even "apply" from the online
redo log faking it to be an archivelog.
Hemant
At 11:01 PM Friday, Mark W. Farnham wrote:
<snip>
In all cases, ensure that you HAVE CORRECTLY CREATED THE CONTROLFILEs,
naming every DataFile -- once you OPEN, Oracle does a Data
Dictionary check and any
datafile in the Data Dictionary but not in your Controlfile becomes
a "MISSING" datafile !
{so sometimes we do another backup, if we can, before the OPEN RESETLOGS !}
<snip>
Regarding the extra backup: This is also why, whichever side you are on in
the quasi-religious argument about whether online redo logs should be backed
up, the first step of recovery is to secure a copy of the quiescent images
of the online redo logs (most safely apart from your backup media and most
conveniently online) since they contain data that is permanently lost upon
the execution of the open resetlogs command. Whether you (unlikely) crash
restarting or experience PEBKAC during the recovery, having a copy of the
logs as they exist before the restart gives you at least a chance to try
again.
Regards,
mwf
PS: PEBKAC, first heard by me from Mike Brown, Problem Exists Between
Keyboard and Chair. Similar meaning to CFT (controlled flight into terrain)
with fewer tragic overtones.
Hemant K Chitale
http://web.singnet.com.sg/~hkchital
and
http://hemantscribbles.blogspot.com
and
http://hemantoracledba.blogspot.com
"First they ignore you, then they laugh at you, then they fight you,
then you win" !"
Mohandas Gandhi Quotes
: http://www.brainyquote.com/quotes/authors/m/mohandas_gandhi.html
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