RE: RMAN: I don't trust it

I dumped my "home grown" scripts pretty soon after Oracle released RMAN (after they fixed a number of early defects of course) and have never looked back. Although the RMAN scripting language is yet another language to learn it is well worth the effort. It allows you to backup an entire database with a surprisingly small number of commands (in the order to 5 I think), I doubt a home grown script using shell script or perl could be as simple.

Also you will never be able to match the performance of RMAN with a home grown script simply because you do not have access to the data that RMAN has. Try doing incremental backups or optimising the backup of a data file that hasn't been used. A home grown script will backup entire data files whether used or not, while RMAN will only record the existence of the file, and rebuild the empty file during recovery. These type of optimisation greatly reduce your mean time to recovery.

Recovery is also a lot simpler because RMAN does most of the work for you. I've never had any problems with RMAN locating the correct backup of various files. And because it is simpler, less experienced DBAs (DBA's new to an organisation or more junior DBAs) can have a better chance of recovering a database correctly - if the case should present itself.

Having said all that....it is worth keeping yourself up to date with the latest RMAN defects....it is only software after all. :-)

Cheers,
Craig.

-----Original Message-----
Sent: Tuesday, 11 February 2003 11:39 AM To: Multiple recipients of list ORACLE-L

Lyndon,

Unfortunately Oracle is probably focused more on dealing with large databases with complicated uptime requirements. I can just imagine how long it would take to push 1TB through gzip. Doing a daily backup would require multiple CPU's just to deal with the fact that it would still be zipping up the previous day. There comes a time when an incremental backup makes "really good" sense.

Perhaps we'll have to stick with the RMAN concept until someone tweaks gzip a little further? Oh, and in response to your final comment... I don't think "easy" was (nor should have been) Oracle's number one priority when designing rman.  

                    Lyndon Tiu

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                    Sent by:             Subject:     Re: RMAN: I don't
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                    root_at_fatcity.c

                    om

 

 

                    11/02/2003

                    10:03

                    Please respond

                    to ORACLE-L

 

 

If only Oracle can come up with a Postgresql command such as:

pg_dump dbname | gzip > dbname_backup.gz

Then backups would be easy. I know, I know Oracle can do the same with export, and sqlplus but hell it ain't that easy with Oracle.

--
Lyndon Tiu

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