A Comprehensive RMAN Book which will Remain on the Shelf in an Emergency, February 6, 2009
I finished reading this book about six months ago and delayed writing a review of the book until I had a chance to contrast the contents of the book with the Oracle 10g R2 RMAN documentation and other books on the same subject. I bought the book after reading recommendations by several individuals, and thought that this book was the perfect opportunity to refresh by memory of the Oracle 8i documentation of RMAN and bring me up to speed with the command line interface of RMAN in Oracle 10g R2. The Enterprise Manager Database Control in Oracle 10g R2 almost over simplifies the process of setting up backups, but there is always that nagging question… what if the GUI interface is down, underscoring why it is important to be familiar and comfortable with the command line interface when restore and recovery are needed. I was also preparing to give a presentation related to Oracle administration and performance tuning. This book did not meet the criteria for inclusion in the recommended resources for the presentation, and for that matter neither did any other RMAN book, with the possible exception of the Oracle documentation.
While the book excels at explaining what makes RMAN tick, I personally found that the book is actually a bit difficult to use when trying to implement a change to the Oracle configuration. The section on database cloning, for instance, is more difficult to follow than Oracle’s own “Backup and Recovery Advanced User’s Guide” documentation on the same topic. Maybe it is just me (and one or two other people). Flipping between several pages (seemed like a hundred or more) is not confidence inspiring had this been a real emergency.
I then decided to try a couple recovery scenarios. I set up an Oracle 10.2.0.4 database instance on a new box, used impdp to load a copy of the data from a production database, enabled archived redo log mode, and then scheduled a backup using the Enterprise Manager Database Control. The first test involved shutting down the Oracle instance, and renaming both copies of the control files. The first attempt in following the “Oracle Database 10g RMAN Backup & Recovery” book to recover from this problem resulted in “ORA-07445: exception encountered: core dump [ACCESS_VIOLATION] [unable_to_trans_pc] [PC:0x7c910CB0] [ADDR:0x4] [UNABLE_TO_READ] ”. The book did not cover how to recover from the ORA-07445, which essentially means that Oracle Metalink support must be contacted – the database is down. Not too reassuring. The second attempt (after recreating the instance and database) of following the book to perform this procedure, after realizing that I should have specified RESETLOGS (if I recall correctly, it seems that information was located somewhere else in the book) resulted in “ORA-19698: …\redo01.log is from different datadase: id=0, db_name=” following the execution of ALTER DATABASE OPEN RESETLOGS. Once again, scanning through this book I did not find the solution to this particular problem. Had this been a real emergency, this book would not have been the only object to hit the recycle bin.
Other miscellaneous notes about the book, in no particular order:
- 100+ pages of the book are devoted to setting up RMAN to work with various storage/media managers.
- RMAN workshops list steps to accomplish various tasks, often spread over 5+ pages in the book. Not all required information is located in close proximity to the RMAN workshops.
- Covers command line and Enterprise Manager GUI commands for RMAN.
- Demonstrates flashback versions queries, flashback table, flashback drop, flashback database
- Many screen shots, diagrams, RMAN Workshop break outs, large font – space filling section headings, seemingly wide margins.
- Some steps which should be straight forward, such as duplicating a database using RMAN, appear to be very simple when reading the book, yet when attempting to put those simple procedures into practice using the book as a guide, are in fact quite difficult due to all of the alternate syntax which is introduced to cover many different set ups. It might be necessary to flip between 50 different pages to successfully duplicate a database on the same server using this book as a guide.
- The book does not indicate what features described in the book require an Enterprise Edition license, nor what features require additional licenses beyond an Enterprise Edition license (this seems to happen in several books by different authors).
- In a crisis, the Recovery Case Studies in chapter 21, which could prove to be the most helpful section of the book, but that section only covers 13 scenarios, all with generally a long description to describe the recovery case study problem.
This book is spared a three star recommendation only by the fact that I enjoyed reading the book cover to cover.
Recently, I have been reading “RMAN Recipes for Oracle Database 11g: A Problem-
Solution Approach” and have found that the book is better organized, locating the necessary information in the right places for accomplishing a task, although there is a bit of over repeating in the book (the same sentence appears in two adjacent paragraphs, for example). While the RMAN Recipes book states that it is designed for Oracle 11g, there are output captures which show that some of the sections of the book were written using Oracle 10.2.0.x. If you are considering the purchase of “Oracle Database 10g RMAN Backup & Recovery”, you might first want to examine “RMAN Recipes for Oracle Database 11g: A Problem-Solution Approach” through the Google books search to determine if it is a better fit for your anticipated backup and recovery scenarios.
(The author indicates that the next release will address the clarity of the Cloning section.)