Re: using rman

From: Karsten Farrell <kfarrell_at_belgariad.com>
Date: Tue, 07 Jan 2003 17:27:58 GMT
Message-ID: <y6ES9.701$U75.49586196@newssvr21.news.prodigy.com>

Igor wrote:
> Holger Baer wrote:

>>Considering todays hd prices you better
>>throw in an additional disk just for the backups and use it as primary
>>backup target (which will speed up backup as well).

>
> I suppose, you did not really mean it litteraly, _one_ disk, what do you do
> with db with 200, 500, 1000 GB? One disk? What about CEO that just does not
> accept the "one disk more"?
>

Don't forget that one of the nicer features of rman is that it won't backup all those empty Oracle blocks found in lots of datafiles. Your shell script will copy *every* single disk block in the datafile, whether or not it contains any data. In terabyte databases, you tend to have more empty space (unless the data is pretty static) because you expect lots of data to come flooding in and you don't want to constantly resize datafiles (and you definitely don't want to turn on autoextend).

You can also perform incremental backups in rman ... something you can't do in a shell script.
>

>>The shell script you propose will be much more complex and take much
>>more time to develop - putting tablespaces in and out off backup mode,

>
> Putting tablespaces in/out of backup mode is not really the issue, is it???
> That's just three lines of code ...
>

Yes, 3 lines of code - easy for the shell script coder - that cause all kinds of things to happen inside the db. You see, another nice feature of rman is that it doesn't have to put the tablespace in backup mode, which would require an increased amount of redo generated by your 3 lines of code.

You can also adjust performance with rman by running in parallel or by multiplexing i/o. You can even throttle rman i/o so it doesn't adversely impact o/s i/o.
>
> Have a nice day and thanks for your comments,
> Best regards,
> Igor
>

By the way, I use shell scripts for all my backups ... but hey, I've got the dream DBA job ... small database (after the terabyte ones in my previous job) ... script takes only 15 minutes for full backup of our prod db ... minimal DBA intervention required ... more disk space than I need ... time to read the docs. Received on Tue Jan 07 2003 - 11:27:58 CST