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Home -> Community -> Usenet -> c.d.o.server -> Re: Online backup: Backup online redologs?
I use shutdown immediate. I only use shutdown abort if shutdown immediate fails. I've seen shutdown immediate hang a session and not shutdown the database. With server manager I can start another session and shutdown abort. With SQL*Plus I've gotten the message that the database is shutting down, and I can't start a new session even as internal. In 9i we won't have server manager or internal. I guess the only recourse there will be to stop the service at the OS level.
Best!
Randall
Charles J. Fisher <cfisher_at_rhadmin.org> wrote in message
news:Pine.LNX.4.33.0106100922500.13875-100000_at_galt.rhadmin.org...
> On Fri, 8 Jun 2001, Ravi Sista wrote:
>
> > PS : I tend to agree with Howard on this one. I don't think the way you
> > shut the database down matters (as long as it is down, when you started
> > the cold backup) when it comes to the validity of your cold backups. Any
> > one else with an opinion on this one? Thanks in advance.
>
> Couchman has been wrong many times, but here are his comments from the 8i
> OCP book:
>
> "Oracle uses SCNs in control files, datafile headers, and redo records.
> Every redo log file has both a log sequence number and low and high SCN.
> The low SCN records the lowest SCN recorded in the log file, while the
> high SCN records the highest SCN in the log file. CKPT writes those
> numbers to the datafiles and to the control file. The checkpoint number is
> also written to the redo log file. When the database starts, all
> checkpoint sequence numbers in all datafiles, redo log files, and control
> files must match. If they do not, Oracle will not start, and you must
> perform media recovery on your database to get the files synchronized and
> in a consistent state." (p. 669)
>
> This seems to imply to me that interrupting an in-flight checkpoint with a
> shutdown abort can be deadly.
>
> In an apparent contradiction, he goes on to say:
>
> "A point was made earlier that SMON will perform instance recovery if it
> detects that the datafiles are not synchronized. Recall that part of the
> work done in a checkpoint is to write the SCN to datafile headers and copy
> data in the buffer cache and log buffer to their respective disk files.
> This process synchronizes all Oracle files. If the instance crashes, these
> files will not be synchronized because Oracle did not have the opportunity
> to synchronize them before the instance failed. SMON will synchronize them
> for you automatically." (p. 678)
>
> To me, it is unclear where out-of-phase checkpoint information requires
> instance recovery (SMON) or media recovery.
>
> ----------------------------------------------------------------------
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