RMAN automatically optimizes a
DUPLICATE
command that is a repeat of a previously failed DUPLICATE
command. The repeat DUPLICATE
command notices which datafiles were successfully copied earlier and does not copy them again. This applies to all forms of duplication, whether they are backup-based (with or without a target connection) or active database duplication. The automatic optimization of the DUPLICATE
command can be especially useful when a failure occurs during the duplication of very large databases.
If a
DUPLICATE
operation fails, you need only run the DUPLICATE
comand again, using the same parameters contained in the original DUPLICATE
command.
The second
DUPLICATE
operation locates the datafiles that were successfully duplicated by the initial DUPLICATE
command. Restores only the missing or incomplete datafiles, thereby avoiding re-copying and restoring all the datafiles.
Before you attempt to resume a failed
DUPLICATE
operation, you must reset the auxiliary instance to NOMOUNT
mode. One way to do this is to exit RMAN, use SQL*Plus to reset the auxiliary instance to NOMOUNT
mode, start RMAN and then repeat the DUPLICATE
command. If you do not want RMAN to automatically recover from a failed DUPLICATE
operation, specify the keyword NORESUME
to disable the functionality. Using the keywordNORESUME
in the first invocation of DUPLICATE
prevents a subsequentDUPLICATE
command for the new database from using this automatic optimization.
Great article!
ReplyDeleteVery Useful update
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