Re: How to do an online backup?

From: Jeremiah Wilton <jeremiah_at_wolfenet.com>
Date: Sun, 31 Oct 1999 08:08:30 -0800
Message-ID: <381C697E.C7571482@wolfenet.com>

> On Mon, 25 Oct 1999 18:28:42 +0100, "Eric Dantie" wrote:
>
> >ALTER TABLESPACE tablespacename BEGIN BACKUP
> >
> >do your copy
> >
> >ALTER TABLESPACE tablespacename END BACKUP

Robert Klute wrote:
>
> Basically right, but there are a few more steps to the process, if you
> want to be able to do a full recovery.
[... many steps deleted ...]
> ALTER SYSTEM SWITCH LOGFILE;
I think the best command for archiving the current online logs is ALTER SYSTEM ARCHIVE LOG CURRENT. If you use ALTER SYSTEM SWITCH LOGFILE, and start copying archives right away, you have no guarantee that the current logs have been completely archived. The archival begins after the command returns, but by then you are already off and copying logs, which could result in incomplete or missing logs in a backup.

ALTER SYSTEM ARCHIVE LOG CURRENT will not return until the current log has been archived, so if a script is smart enough to wait for that command to return, it can be guaranteed to get all the logs, providing a valid backup.

--
Jeremiah Received on Sun Oct 31 1999 - 10:08:30 CST