FW: Backup VLDB's

From: Mark W. Farnham [mailto:mwf_at_rsiz.com] Sent: Tuesday, November 10, 2009 6:39 AM To: 'hrishys_at_yahoo.co.uk'; 'gnahmed.c_at_stc.com.sa'; 'oracle-l_at_freelists.org' Subject: RE: Backup VLDB's  

Usually when I hear or read the question "what is the fastest way to back up?" the person should be asking "what is the fastest way to recover?" As long as the process of taking a backup does not affect throughput and response time in a material way, how long it takes is only relevant in the context of "how fast can I deliver the required repair." Again, though, that is recovery, not backup. How often, and under what circumstances, will a full reload be required? How often, and under what circumstances will a block repair be required? Think that through and design a recovery process that meets your operational requirements and can be explained to and understood by management. Triage of what to recover in what order is also germaine in the context of restoring operations. There is a reason why Oracle invested the effort to make it possible to get a database back up and running with a few key tablespaces and files. Priority of recovery of the tablespaces after that should take into account which operational features cost a company the most per hour to have down. If your backup design cannot restore files with priority without scanning lower priority files, that represents a limitation to restoration flow. Whether that limitation is important in dollars and cents is another issue. And of course your overall system architecture with the possibility of standby databases held at varying archive application delays may make the need for a full restore vanishingly small even in the face of application error or sabotage. But thinking these things through and deciding what your recovery requirements are should be upstream of working on the sheer speed of the backup. Of course it should not be overlooked that in some cases the fast technology based backup means that a fast restore is simply the reverse operation.  

Hrishy's comments are on target. Money equals speed. Or maybe money plus brains equals speed.  

Oracle's recovery capabilities are an enduring technological marvel in conception, architecture, programming, and execution.  

mwf  

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