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Sync vs. Async Test

Notes:

One of the methods of monitoring performance of RMAN operations is the V$BACKUP_ASYNC_IO view. Each row containing TYPE “AGGREGATE” provides statistics on a channel operation, including elapsed time and data transfer speed (“effective bytes per second”). To test the performance gain of enabling asynchronous I/O to tape, first I ran a backup using synchronous I/O.
The supplied script v$backup_sync_io.sql generated the first report shown in the slide:
sys@TEST> select to_char(close_time, 'mm/dd hh:mi') as time, type,
2 elapsed_time as et,effective_bytes_per_second as eb
3 from v$backup_sync_io
4 where close_time > sysdate - (1/24 / 4) /* within last .25 hour

Notes for this slide continue on the next page…