Re: Are offline backups an option, or a neccessity?

In article <879877004.8521_at_dejanews.com>, <tashkop_at_iname.com> wrote:
>We are about to implement SAP over Oracle with a 24*7 requirement. I am
>advised by the basis consultant of the implementation partner that we
>should be taking the RDBMS offline at least once a week for an offline
>backup, *or*, we need three times the amount of disk to carry out some
>kind of complicated rolling type backup. This is in spite of the Oracle
>RDBMS supporting an online backup mode, which we are advised to carry out
>nightly.
>
>Is it really neccessary to take the system offline regularly to do a
>backup? Can the online backups alone be relied on for a robust solution?
>
>I need to get my head around the issues here as the consultant said 'the
>RDBMS supports an Online backup no problem' then in the next breath is
>advising to take the system down regularly, or triple our disk budget.
>
>We would rather not do either if we can reliably not do so.
>
>your advice is appreciated.
>
>TIA
>rgds
>
>

Well, the real issue is the restore. You have to be able to restore to a known point, then roll forward to the desired point. So, if you have some real time constraints, triple-mirror your system, then to do backup, alter tablespace begin backup, break the third mirror, end backup, then do the physical backup from the broken mirror at your convenience. Then resilver. If you've already got mirrors, it would only increase the disk budget by 50%. :)

Compare your disk budget to your DBA/admin salaries. And, is it truly 24/7?

I must say, the Oracle Press Backup book really helps.

>Peter Tashkoff <tashkop_at_iname.com>
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>All rights reserved. No party may use this document to vilify another.
>
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