Re: Backup using only one CPU - SA wants to know why

From: David Fitzjarrell <>
Date: Mon, 12 Nov 2012 12:13:09 -0800 (PST)
Message-ID: <>

One question I have is how many cpus does Oracle think there are?

David Fitzjarrell

From: Sandra Becker <> To: oracle-l <> Sent: Monday, November 12, 2012 12:38 PM Subject: Backup using only one CPU - SA wants to know why

SLES11 on IBM mainframe
DB size - just below 1T
I run an incremental 0 backup on my production OLTP once a week, incrementals the rest of the week.  Recently changed the disk_asynch_io to TRUE and the filesystemio_options to SETALL, per recommendations from Oracle.  I then added a channel to the backup scripts so it uses 4 channels.  These changes shaved 35 pecent off the time it takes to run the incr0 backup, which I am very happy with.

The SA monitoring the performance of the mainframe says the incremental 0 backup of our production OLTP is pegging a single CPU, out of 5 available. He thinks the backup would run even faster if it used more CPUs and suggested setting the PARALLELISM parameter to more than 1.  Unbeknownst to him, it had been set to 3 for the past 6 years.  He wants to know why the backup isn't using more CPUs.  Any ideas/suggestions?


Transzap, Inc.


-- Received on Mon Nov 12 2012 - 21:13:09 CET

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