Re: Are offline backups an option, or a neccessity?

> If I'm wrong about my following statements - do not hesitate...
>
> 1. Tablespaces are taking offline during Hot Backup. Any DML changes during
> the copying of the tablespace's underlying files are written to the Redo Log
> Files.
>

I'm afraid this is not entirely true. What you should actually be doing is issuing the commands;

alter tablespace <tbsp_name> begin backup; --NOT offline !OS copy/backup of underlying OS files
alter tablespce <tbsp_name> end backup;

for each tablespace in turn.
Whilst the tablespace is in backup mode whole blocks that are affected within the tablespace rather than individual items are written to the re-do logs to ensure consistency therefore the more DML statement that occur the more re-do that will need to be written.

> 2. To Guarantee 100% of sucessful Hot Backup, these Redo Logs should be backed
> up as well.
>

True.

> 3. Therefore, we're doing Hot Backups - and only hot backups - everyday, doing
> the
> following :
>
> - taking each tablespace offline & backing its files
> - and then :
> - find out current log file
> - alter system switch log file
> - alter database backup control file to 'backup area'
> - copying switched log file to 'backup area'

As I have mentioned before I think the command;

alter database backup controlfile to trace;

should be part of every backup strategy as it gives the SQL required to rebuild (or modify) an existing control file.

Regards,

Ian Received on Tue Nov 25 1997 - 00:00:00 CST