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Home -> Community -> Mailing Lists -> Oracle-L -> 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
Gene Sais <Gsais_at_co.palm-beach.fl.us> wrote: my backup strategy, fwiw:
prod - cold monthly, hot 2x week, exp weekly. test - cold, hot, exp occassional, always can refresh from prod. dev - cold & hot occassional, exp daily.
all dbs are in archivelogmode!
gene
>>> keithpson_at_yahoo.com 05/24/02 03:04PM >>>
lets not forget the classic "exp".
Keith
Date: Fri, 24 May 2002 09:12:02 -0800
To: "Multiple recipients of list ORACLE-L"
Reply-to: ORACLE-L_at_fatcity.com
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Organization: Fat City Network Services, San Diego,
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Hi Tim and Connor,
Thanks you all for your very helpful feedback. I do appreciate it very much. In fact, we are in development at this point, so the database is small and transaction volume is very low. Therefore, my choice for primary backup method is the cold backups. However, to safeguard against unsual things, which might happen to the database, I will take your advice to run my database in ARCHIVELOG mode. The hot backup will be used. Again, thanks for your very quick responses.
Regards,
Trang
Tim Gorman wrote:
Trang,
Theoretically, the online redo log files are be necessary, but the world has a habit of making a shambles of the theoretical. Let's say, in the event that you automate your Friday script, you'll probably come to realize that SHUTDOWN IMMEDIATE is far from perfect (as well as far from immediate!). Over time, you'll probably construct some kind of "fail-safe" mechanism to SHUTDOWN ABORT if the initial SHUTDOWN IMMEDIATE doesn't shut down after a period of time. Pretty standard thing that DBAs have been writing for years. Hopefully, after the SHUTDOWN ABORT they also STARTUP RESTRICT and then SHUTDOWN NORMAL, but you can't count on it...
So, here's the point: what if you take a cold backup in NOARCHIVELOG mode after a SHUTDOWN ABORT (that should have been a SHUTDOWN IMMEDIATE and wasn't) and you have *not* backed up those online redo log files? Answer: unusable backup. So, back up everything: all datafiles, controlfiles, and online redo logfiles. The latter are not too big anyway -- what's the point of excluding them?
It is wise to take a cold backup after a clean shutdown, but you can even get a valid backup after a SHUTDOWN ABORT or a crash if you've backed up the online redo archive log files. When you restart Oracle, an instance recovery will occur automatically, and you might not even know it. Just be certain that the instance is truly "dead" when you take your "cold" backup...
With regards to switching between ARCHIVELOG and NOARCHIVELOG, it's a waste of effort from a recoverability standpoint. At most it may be interesting, but as soon as you switch out of ARCHIVELOG mode, nothing you've done while in ARCHIVELOG mode is valid anymore. Leave it one way or the other, and then leave it...
...just my $0.02...
Another $0.02: use RMAN for your cold backups. Then you won't forget anything, because RMAN will remember for you...
Hope this helps...
-Tim
----- Original Message -----
To: Multiple recipients of list ORACLE-L
Sent: Thursday, May 23, 2002 5:33 PM
Hi All,
I need to perform a consistent backup for my whole database every Friday by using operating system utilities. My database has been currently operating in NOARCHIVELOG mode, so the only files need to be backed up are datafiles, control files, the initialization parameter file and other oracle product initialization files (Based on Oracle8.1.6 Backup and Recovery Guide). Since the files in this type of backup are all consistent and do not need recovery, so the online logs are not needed. Since online redo logs is very crucial for recovery, so my question is do I need to back up the online redo log files as I choose to perform cold backup type for my entire database weekly? Here is step by step what I did to back up the whole database:
after the database was closed cleanly and all the above mentioned files had been backed up into the tape. I had to restart the database and mount but not open, then switched between NOARCHIVELOG mode to ARCHIVELOG mode in order to archive the online redo log files. Finally, I copied all archived redo log files into the tape while the database was open and operated in ARCHIVELOG mode. when it was all done, I then switched the database back to NOARCHIVELOG mode. Just wondered whether my procedure to perform a whole consistent database backup is correct? Am I safe to this point? Your help is greatly appreciated it. Your help is greatly appreciated.
Thanks in advance,
Trang
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Keith Peterson INET: keithpson_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Gene Sais INET: Gsais_at_co.palm-beach.fl.us Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). --------------------------------- Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Meomeo Nguyen INET: meomeo22_at_yahoo.com Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Fri May 24 2002 - 15:53:45 CDT
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