Oracle-L: RE: Database backup question.Thank You

From: Steve McClure <smcclure_at_usscript.com>
Date: Fri, 24 May 2002 15:33:22 -0800
Message-ID: <F001.0046B6E2.20020524153322@fatcity.com>

Allright,

My response wasn't meant to confuse you. I will try to do better. a cold backup -- by definition taken when your database is shutdown. The shutdown process is normal. If you shutdown using shutdown immediate or abort you will need your online redo logs in order to recover from this backup. It is generally recommended that you startup restrict the database after this and then shutdown normal. This will ensure you have a "clean" backup. The cold backup should include your data files, control files, your archived redo logs(if in archivelog mode), and your online redo logs. Again your online redo logs aren't technically required, but wouldn't we all feel stupid if being technically correct cost us a clean recovery, so back them up as well.

ok now hot backups. Hot backups are made with your database up and running. This kind of backup requires you to place your tablespaces in backup mode. This can be done manually or through scripting. Your database is required to be in archivelog mode, in order for this kind of backup scheme to work. Since your database is up and running while it's files are being copied, it is by definition an inconsistent backup. Oracle will use archived logs to recover from this kind of backup.

As I said before you can place your DB in archivelog mode and back it up cold. If fact I would recommend doing it this way for a while, until you are comfortable with the backup/recover process. I highly recommend you check into Rama Veluri's "Oracle Backup and Recovery Handbook". You should at least refer to the Oracle Backup and Recovery guide.

Good Luck,

Steve McCLure
  -----Original Message-----
  From: root_at_fatcity.com [mailto:root_at_fatcity.com]On Behalf Of Meomeo Nguyen   Sent: Friday, May 24, 2002 1:54 PM
  To: Multiple recipients of list ORACLE-L   Subject: Re: Database backup question.Thank You

Thank you all for your responses. You all really confused me about this issue. The whole database backups can be consistent or inconsistent. To perform a consistent whole databse backup is the only valid backup option for databases running in NOARCHIVELOG mode. In contrast, an inconsistent backup is valid if the database is running in ARCHIVELOG mode. So, my question is why having my databse running in the ARCHIVELOG mode, I can still perform both consistent and inconsistent backup options?

Steve posted :

"I don't understandy why you would switch to and from archivelog mode. You can establish a complete cold backup with your datafiles, control files, and online redo logs. Actually you don't need the online redo logs, but that used to be the case so I always back those up as well. Shut your DB down (normal), and back these files up. That is a complete cold backup."

Steve, I switch to and from archivelog mode because the best way to back up the contents of the current online redo log is always to archive it, then back up the archived logs. Again, I do appreciate you all for your help. I do need very clear picture about this issue. Since I have not done anything like this before so I do need your feedback badly.

Thanks in advance

Trang

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Author: Steve McClure
INET: smcclure_at_usscript.com

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