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Yes is the simple answer.
Compression can take a lot of time depending upon the data stored. Try zipping a zip file for example, it is generally slower on the second pass.
SELECT ALGORITHM_NAME, ALGORITHM_DESCRIPTION, IS_DEFAULT FROM V$RMAN_COMPRESSION_ALGORITHM;
Thanks for your attention, we disabled the compression in our backup and it did run faster.
I would like to know another thing, if possible: Is there any rule to determine the correct number of channels. I know each channel creates a session and paralellize the backup. For example, the number of channels is related to the number of cpu cores? ... or the number of output devices?
Thanks again in advance.
Hello again;1 person found this helpful
For disk backups allocate one channel for each physical disk.
The exception to this rule is if you can optimize the backup for your disk subsystem architecture with multiple channels.
Failing to allocate the right number of channels adversely affects RMAN performance during I/O operations.
Thanks for your attention and pacience.