Making Decisions
Oracle Databases and Backups
I have now had several months of experience as an Oracle DBA, and my advice is backup frequently. The general concept I use in my day-to-day administration is very simple, and is very much the general practice in the administration world. The best strategy would be to do a full database backup using the RMAN tool included in Oracle Standard and Enterprise database products. Once per week, a full database backup is performed, and daily there are incremental backups, to maintain the changes that have occured to the databse that day. Since the database at work is used internationally, a “run at night” solution is not the most feasible or effective solution, so I have looked at peak load times, and have tried to schedule my backups to occur during general periods of low usage. Also for quick manual backups, I quite enjoy the new expdp and impdp utilities in Oracle 10.2g and 11g, as they allow for fast, easy manual backups. The only word of warning is that these database utilities are not naturally consistent nor do they use the old exp and imp tools consistent=’Y’ feature.
To ensure data consistency and integrity you should use the flashback feature. It supports both SCN (system change number) and dates. When using flashback_date, it takes the timestamp and finds the most recent SCN to that time, so basically it just extends SCN. To find your current SCN, you can just run the following stored procedure from SQL*Plus: SELECT CURRENT_SCN FROM V$DATABASE;
That being said, I feel that Oracle makes a fantastic business level database solution. For most independent developers it seems a bit much, as well as the Oracle XE is very restrictive on database sizes at 1GB maximum, a small database can exceed that quite quickly. But their Standard and Enterprise products are fantastic, and would recommend it to anyone as a standard database over MSSQL and MySQL in the corporate world.
