Re: hot backup question

Hi Peter,

Since it is unwise to read the current Redo Log file while it is still being written to (due to inconsistencies), I get round this by; 1. Perform a manual Log Switch prior to starting the Hot Backup 1a. Put all Archived Log files onto the backup media (optional if you can, otherwise leave until step 5).

2. Perform the Hot Backup as per current methods
3. Perform a manual Log Switch after the Hot Backup
4. Create the backup controlfile
5. Put the Archived Redo Log files and Backup Control file on to the backup

In this way, if you need to recover from this backup, you know that all the Redo Log files that will be needed are available (not still current and online) due to step 3.
If you loose the Control Files, then you have at least the Backup Control File from when the database was backed up, step 4. You also know that recovery starts from Archive Log file taken in step 1, and if you want, you can erase all previous log files. I use this number for the next backup, so I know that if the Backup is corrupt, I can get the backup from before and still recover with all Log files.

Andrew

Peter Liu wrote:

> Hi,
>
> My question is: when doing a hot backup, do I need to back up online
> redo log files besides achieved redo log files? In the book "Oracle
> Unleashed", all online redo logs are needed to make a backup. But in the
> book "Oracle8 DBA Handbook", it seems that it is not necessary to back
> up online redo logs.
>
> Thanks for your response.
>
> Peter
Received on Fri May 14 1999 - 20:24:14 CDT