Enabling archive log

Question

Hi all,
1) How to enable archive log in oracle 10g. Found a link in google. http://cuddletech.com/articles/oracle/node58.html
Is it the correct way, need to down the database.
2) Could the archive log affect the performance of the database, if i have average of 1 write transactions to the database? I have a database that have already switch on by my precessder. I notice that it generate a 40,000kb of file every 3 minutes.

Answer 1

The questions are, how often are your redo log switches, are the users noticing a performance issue, what level of service have you agreed to for backup and recovery?
There can be trade-offs made, depending on the exact circumstances. As Ed noted, not losing data is the prime directive. There are many ways to avoid losing data, someone has to decide which are most appropriate and which are just too expensive. Someone playing what-if scenarios with your projected budgets is going to have a different idea about that than someone who is in charge of millions of dollars of online orders. DW and DSS systems often have other places to get the data and may not require being able to point-in-time recover. It depends.
What you need to avoid is managers saying things like "we only care about restoring to last nights backup," when they don't understand what they are saying.
Some bulk-loading situations can benefit from nologging operations, and some (like a massive update in an app upgrade) can benefit from going out of and into archivelog mode, since such things can generate huge amounts of redo without a requirement to recover halfway through them. Just be sure and take an appropriate backup after such things. That also means, take a backup as soon as you go into archivelog mode.