| Online backup [message #172408] |
Tue, 16 May 2006 07:06  |
gajini
Messages: 262
Registered: January 2006
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Senior Member |
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I've read the following lines,"During user managed online backup,we need to keep tablespace in backup mode,so this more redo will be generated since whole changed block details will be recorded in it but this problem is overcome if we use RMAN"
please anyone explain me in detail,
1) How RMAN do online backup,if it doesn't take tablespace in backup mode?
2) If we use RMAN,during online backup where changed block details will be stored if it's not in redo logs & how it's working?
It's very urgent,please clear my doubt.
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| Re: Online backup [message #172424 is a reply to message #172408] |
Tue, 16 May 2006 07:55  |
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ebrian
Messages: 2794
Registered: April 2006
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Senior Member |
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As was posted elsewhere:
1. RMAN does not need to put the tablespaces in BACKUP mode, because it utilizes what is called Fractured Block detection. RMAN determines whether a block is fractured by reading it's header & footer. If it detects a fractured block, then it rereads the block until it gets a consistent picture of the data.
2. Recovery Manager records the SCN at the point-in-time the backup of the datafile started, in its own
Recovery Catalog in the control files.
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