Re: archivelog backup and its files

Chris,

You are doing nothing wrong.

The archivelog files are created as copies of the old online log files once oracle is finished with them. No archivelog files will be created until after a log file is switched, either automatically by oracle or manually be you. During an online backup additional information that is needed by Oracle during a restore is written to the log files, without this information you will not be able to recover. However you can't backup an online logfile while the database is open and depending on how busy your system is some of the information may have been archived while your backup was in progress. That's why HJR's procedure has an "alter system switch logfile;" at the end to move the last lot of required information into an archivelog file. Thus your very last step should be to back up all the needed archive log files, starting with the most recent one that existed prior to the backup starting and ending with the last one you created with your switch logfile command.

Kind Regards

Fraser McCallum
MVP Oracle Administration
www.brainbench.com

"obakesan" <cjundieseastwd_at_powerup.com.au> wrote in message news:tq968.6782$T4.65733_at_nnrp.gol.com...
> HiYa folks
>
> I am having some trouble with the basics of back up and recovery
> and since this is the first time I have done any of this I thought
> that I would ask a simple question.
>
> I have been following the guidance of the document by HJR
> who suggests that a hot backup sequence be something like this
> (from SQLPlus)
> alter tablespace mydata begin backup;
>
> (from the os copy the file somewhere)
>
> (from SQLPlus)
> alter tablespace mydata end backup;
> alter system switch logfile;
>
>
>
>
> now, my problem is this, I have just changed a new database to be in
> archivelog mode by using the following
> sqlplus /nolog
> SQL>
> SQL>startup nomount
> SQL>alter database mount
> SQL>alter database archivelog
> SQL>alter database open
> SQL>alter system arvhive log start
>
> and of course edit the file init$ORACLE_SID.ora to add the lines
>
> log_archive_start = true
> log_archive_dest = "/u01/app/oracle/admin/DEV/arch"
> log_archive_format = arch_%t_%s.arc
>
> now my problem is, that there is no file in the log archive dest after
> I have done this procedure, have I done something wrong?
>
> I wasnt sure, so I tried issuing the command
> alter tablespace mydata begin backup;
>
> which didn't make any file either
>
> I then took the next step of
> alter tablespace mydata end backup;
>
> and then
> alter system switch logfile;
>
> and lo and behold a file appears in the location.
>
> so my question is "is his order right or am I doing something wrong?"
>
> do I have to change file first, then backup that changed file??
>
>
> Thanks folks
>
>
> See Ya
>
> --
> (when bandwidth gets better ;-)
>
> Chris Eastwood
> Photographer, Programmer, Motorcyclist and dingbat
>
> please remove u n d i e s for reply
Received on Thu Jan 31 2002 - 07:59:12 CST