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Re: Different backup procedure.

From: David Shi <dshi_at_magpage.com>
Date: 11 Aug 1998 01:09:02 GMT
Message-ID: <6qo5je$rjv$0@208.222.91.197>


In my dept, a software does all the backup automatically, it is not possible to have script to do "begin backup" "end backup" sequence. My question is, is it ok to do an "begin backup" on all the tablespaces and then do a whole datafile backup?

I think I read somewhere this is not recommended, can any one give me a little insight into this? Thanks.

David

On Fri, 07 Aug 1998 22:40:46 -0500, "John P. Higgins" <jh33378_at_deere.com> wrote:

>You MUST use archivelog mode to do hot backup.
>
>When you do hot backups, the database is up and users are updating!
>
>The basic hot backup script is:
>
> for each tablespace
>
> alter tablespace _______ begin backup:
> for each datafile of the tablespace
>
> tar, cpio, dd, .... the file
>
> next file
> alter tablespace _______ end backup;
>
> next tablespace
>
>Since the users are updating while the backup is running, the backup is
>'fuzzy'. That is, the backup files are not from a single, consistent
>point-in-time. So, if you restore all the database files from your hot
>backup, you will need to apply the redo logs (recovery) that were created
>during the backup. (You may need to apply even more logs, depending on the
>point-in-time to which you are recovering.)
>
>This is why you need archivelog mode for hot backups: archivelog mode
>ensures that you still have the redo log data that you need for recovery.
>
>_____________________________________________________________________
>
>Backups enable recovery. If you don't need recovery, you don't need backup!
>
>Cold backup enables recovery to the point-in-time of the cold backup.
>Without archivelog mode, no further recovery is possible. With archivelog
>mode, you can recover to any point-in-time up to current time.
>
>Hot backup enables recovery to the point-in-time where the hot backup
>terminated. Since this requires archivelog mode, you can recover to any
>point-in-time up to current time.
>
>Archivelog mode enables recovery of the work since the last hot or cold
>backup. If you can afford to lose all work since the last backup, you don't
>need archivelog mode!
>
>Archivelog mode also enables hot backup. If you can shut down your database
>long enough for a cold backup, you don't need hot backup.
>
> John
>
>giau45_at_yahoo.com wrote:
>
>> I keep reading on Oracle backup procedure. And I'm still fuzzy about
>> hot backup and archive mode.
>>
>> Cold backup: shutdown all DB and do a complete copy of dbf files (as I
>> understand it)
>>
>> How is backup work and archive log mode work ? Thank you.
>
Received on Mon Aug 10 1998 - 20:09:02 CDT

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