Re: Online Backup question

"Jan Gelbrich" <j_gelbrich_at_westfalen-blatt.de> wrote in message news:c1f1g2$1gkuji$1_at_ID-93924.news.uni-berlin.de...
> Hello,
>
> I would like to hear some opinions about online backup ordering.
> Which "style" is better (safe, fast) ?
>
> This one ?
>
> I.
>
> ALTER TABLESPACE SYSTEM BEGIN BACKUP;
> ALTER TABLESPACE RBS BEGIN BACKUP;
> ALTER TABLESPACE TEMP BEGIN BACKUP;
> ALTER TABLESPACE TOOLS BEGIN BACKUP;
> ALTER TABLESPACE USERS BEGIN BACKUP;
> and so on ...
>
> !cp /u01/oradata/ora8/system01.dbf /var/backup
> !cp /u01/oradata/ora8/system02.dbf /var/backup
> !cp /u01/oradata/ora8/rbs01.dbf /var/backup
> !cp /u01/oradata/ora8/rbs02.dbf /var/backup
> !cp /u01/oradata/ora8/temp01.dbf /var/backup
> !cp /u01/oradata/ora8/tools01.dbf /var/backup
> !cp /u01/oradata/ora8/users01.dbf /var/backup
> and so on ... about 15 more dbfs follow.
>
> ALTER TABLESPACE SYSTEM END BACKUP;
> ALTER TABLESPACE RBS END BACKUP;
> ALTER TABLESPACE TEMP END BACKUP;
> ALTER TABLESPACE TOOLS END BACKUP;
> ALTER TABLESPACE USERS END BACKUP;
> and so on ...
>
> ... or this one ?
>
> II.
>
> --Backup Setting per Tablespace
> ALTER TABLESPACE SYSTEM BEGIN BACKUP;
> !cp /u01/oradata/ora8/system01.dbf /var/backup
> !cp /u01/oradata/ora8/system02.dbf /var/backup
> ALTER TABLESPACE SYSTEM END BACKUP;
>
> ALTER TABLESPACE RBS BEGIN BACKUP;
> !cp /u01/oradata/ora8/rbs01.dbf /var/backup
> !cp /u01/oradata/ora8/rbs02.dbf /var/backup
> ALTER TABLESPACE RBS END BACKUP;
>
> ALTER TABLESPACE TEMP BEGIN BACKUP;
> !cp /u01/oradata/ora8/temp01.dbf /var/backup
> ALTER TABLESPACE TEMP END BACKUP;
>
> ALTER TABLESPACE TOOLS BEGIN BACKUP;
> !cp /u01/oradata/ora8/tools01.dbf /var/backup
> ALTER TABLESPACE TOOLS END BACKUP;
>
> ALTER TABLESPACE USERS BEGIN BACKUP;
> !cp /u01/oradata/ora8/users01.dbf /var/backup
> ALTER TABLESPACE USERS END BACKUP;
>
> and so on BEGIN+cp+END...
>
> -----
>
> I am very much in favor of the second style, because
> it minimizes the time that a tablespace is in backup mode.
>

Hi Jan

Agreed as this means you reduce redo overheads as Oracle takes copies of before/after images of each new changed block in it's redo stream to recover from fractured blocks whilst a tablespace is in backup mode (unless you use RMAN). Look for a post about 12-18 months ago where I explained why this is the case.

I would however question taking backups of your temp tablespace, it suggests they're not really temporary tablespaces.

Cheers

Richard Received on Tue Feb 24 2004 - 06:18:39 CST