Re: Poor Backup Performance

See
http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96566/rcmtunin.htm#448792

Check the 9206/7 readmes for bugs having to do with shared pool. Research your filesystem configuration in the metalink bug database.

I think the large pool doc is slightly misleading, as it assumes there are no shared pool bugs. So, your large pool is not set, RMAN tries to get memory from your shared pool, which is perhaps having housekeeping issues at random times. This is all speculation, of course, but I'd try following that formula in the doc for setting the large pool, as well as watching the shared pool (
https://metalink.oracle.com/metalink/plsql/showdoc?db=NOT&id=30487.1 for example, OEM has shared pool resource advisor for pretty pictures, and of course, v$shared_pool_advice) before and after setting the large pool.

Let us know if it makes a difference.

jg

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