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Home -> Community -> Usenet -> c.d.o.server -> Re: Online backup: Backup online redologs?
> Howard, I suggest that you examine oraback.sh at backupcentral.com.
Personally, I would only rely on my own tried and true backup scripts. I am well aware that other scripts are perfectly fine. Call me paranoid, but I'd investigate any script found on the Web before I take it as gospel and implement it with blind faith. Especially where backups are concerned.
> From their description:
<<snip>>
> They do go on to say:
>
> -------------------------------------------------------------------------------
> If it's a cold backup...
>
> The script then backs up the control files and redo logs the same way it
> does during a hot backup. This is perhaps the only time that manually
> copying the control files and online redo logs does any good.
> -------------------------------------------------------------------------------
Right here is exactly what Howard has been saying! "This is perhaps the only time that manually copying the control files and online redo logs does any good." You can only consistently copy the online redo logs when the database is down!!! You can not obtain a consistent copy of the online redo logs when the database is up. Even your definitive source that you cite doesn't agree with your opinion.
> I'm not saying that I agree with everything they are doing (I don't see
> why anyone would use an OS copy of the controlfile).
You don't see why anyone would use an OS copy of the controlfile?????
> p.s. You are also wrong in saying "The absolute way of ensuring the
> current redo log is safe to copy is, of course, to shut the
> database down completely: now it's cold, and of course the copy
> results will be consistent." - If the database was brought down
> with a shutdown abort, the active online redolog will NOT be
> consistent.
You are confusing the term "consistent" here. There is a difference in a file being consistent during a backup and the online redo log containing consistent data. A redo log backup being consistent means that the data has not changed between the start of the copy and the end of the copy. But that does not mean that the data is consistent with the user's transactions. That's a whole different story.
IMHO, there are three definitive sources on backup and recovery as it pertains to Oracle databases. One is Howard Rogers. He taught the class long enough to know as much as anyone and has proven time and time again in these forums that he is the expert in this area. Two is the guys who wrote the Backup & Recovery book on Oracle Press. And three, is the guys who work for Oracle who's job is to formulate backup and recovery principles. After all, they wrote the code didn't they? All three agree and you are in the minority.
Just my 3.14159265 cents worth,
Brian
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