Re: Standby DB questions

From: Craig Burtenshaw <crb_at_amsa.gov.au>
Date: Fri, 8 Mar 2002 16:19:54 +1100
Message-ID: <7SXh8.40$lk3.1341@nsw.nnrp.telstra.net>

Hi,

<snip>
1) What is a good method to use to delete logs on the standby after they are no longer needed for recovery? Its kind of hard to tell what has been applied without opening the database read only and running a query. I sure there is a better way to do this.

Set up a cron task to remove the .arc files from your archive directory after a certain
time frame. We have set our to 7 days, but you may not have the storage. We have two programs that manipulate the archive logs. One runs every 15 mins, logs into the Prod database executes an 'alter system switch logfile'
The second runs every 30 mins on our Disaster site, this runs 'alter database recover standby database'
then with the 'auto' command on the next line.

2) What methods do people use for failover?

1. Backups of original.
2. Oracle will complain if the sequence is out of order.
3. Pipe your errors or success messages from the second script, look for

appropriate failure messages
the email them to appropriate users.
4. Manual intervention for errors above MAY be required, or there might be a lot of transactions and the
latest archive log hasn't made the distance to the other computer.

2b) Do people change the machine name and reboot or use tns failover? Nope, no, and no. Why would you need to do this? If in the event of the OTHER system crashing, when it is back on line, manually copy
the appropriate files to the OTHER system and manually apply them using the 'alter database recover standby database' command.

Or are there better ways of acomplishing this. You can buy a $250,000 program that will do it for you, but Oracle can flag the correct errors
on your behalf. Only if you want to do dual feeding, both ways with Archive logs would you need
the $250,000 program.

Good luck
Craig Burtenshaw
Unix Systems/Oracle Database Administrator Australian Maritime Safety Authority. Received on Thu Mar 07 2002 - 23:19:54 CST