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archivelog hot and cold backup preparing for a smooth recovery

From: obakesan <cjeastwd_at_powerup.com.au>
Date: 31 Jan 2002 23:25:44 -0800
Message-ID: <666a787e.0201312325.4f71d4d1@posting.google.com>


HiYa

perhaps this has been asked before on this group, but google didnt yeild it, well not with the keywords I tried.

If nothing else someone else may spot this with some of the keywords I have put into this text

I am trying to fully grasp the concepts of the backup procedures, and just keep getting confused byt the Oracle documantation wording, and the wording of other sources. So to be sure to be sure to be sure....

I have a database in ARCHIVELOG mode, and am considering using this procedure

for each important_tablespace in (select name from v$tablespace;) do

    alter tablespace important_tablespace begin backup;

    copy the datafiles* to somewhere safe     

    alter tablespace important_tablespace endbackup;     

    alter system switch logfile;
done

(pardon the pseudocode syntax)

not sure of the frequency of this yet

I thought that what alter tablespace my_data begin backup did, was to stop user processes from writing to the database datafile, so that a backup process could get a copy of it, in a consistent shape.

Also I thought that the only things stored in log_archive_dest/log_archive_format was the old (now perhaps not all needed??) redo logs??

Re-reading HJRs file more he suggests that all I need to do are back up these datafiles (I guess the online reDo Logs he says to ignore are the ones stored in log_archive_dest/log_archive_format or are there some others?), and the control files, password files, and prarmeter files.

as well as my HOT BACKUP, on one night per week, I was thinking of doing something like a full COLD DATABACK up with something like this below, but I wonder if there is any purpose?? Perhaps just a weekly export would be better here instead??

sqlplus <<EOF
connect / as sysdba;
shutdown immediate;
exit;
EOF then squirting these files I previously found in

    select name from V$DATAFILE ;
    select name from V$CONTROLFILE;
    select member from V$LOGFILE;

into tar and off to somewhere safe

start the database back up again with a

sqlplus <<EOF
connect / as sysdba;
startup;
exit;
EOF
(comments welcome on anything you feel like here)

Now, comes my question

Do I need to keep my previous weeks archive redo information, if I am actually shutting down the database and doing a weekly cold backup? can I just keep the relevant weeks redo archives with each backup??

In fact, is there any point in doing the HOT BACKUP at all if I am running in ARCHIVELOG mode, and doing a weekly COLD BACKUP (keeping that weeks archived redo logs). Then I will only need to roll forward from the last cold backup in the event of a failure? If there is no point in doing the hot backup, then I can mix the export and coldbackup at the weekly downtime, and just keep running in ARCHIVELOG mode to roll forward in the event of a crisis and requsite restore.

(scratches head) There has to be something I have missed in this
maybe its the flushing of the re-dolog to the archive ...

Thanks folks Received on Fri Feb 01 2002 - 01:25:44 CST

Original text of this message

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